Ounces to Grams Converter: Exact Avoirdupois, Troy, and Nutrition Label Conversions
Convert avoirdupois ounces to grams using the exact NIST value: 1 oz = 28.349523125 g. Includes troy ounce reference (31.1035g for gold and silver), US FDA nutrition label context, cooking presets, batch mode, and free PDF export.
Ounces to Grams Converter
Enter ounces or grams to convert
1 oz (avdp) = 28.349523125 g exactly. Enter any positive decimal value.
Common US Weights Comparison (Grams)
The Three Types of Ounces Americans Use and Why They Are Not Interchangeable
If there is one measurement unit in the United States that causes more confusion per word than any other, it is the ounce. The average American uses the word “ounce” every day, often without realizing that it can mean three completely different things depending on context. Getting the wrong type can mean the difference between a recipe that works and one that fails, a precious metal transaction that is correctly priced and one that is off by 10%, or a medicine dosage that is safe and one that is not. Before converting any ounce value to grams, you need to know which ounce you are working with.
Avoirdupois Ounce (the Everyday US Ounce)
The avoirdupois ounce is what Americans mean when they say “ounce” in a grocery store, on a nutrition label, in a kitchen, on a bathroom scale, in a shipping estimate, or in a recipe. It is defined as exactly 1/16 of an avoirdupois pound, and since 1959, the avoirdupois pound has been defined as exactly 453.59237 grams by the International Yard and Pound Agreement. Dividing 453.59237 by 16 gives exactly 28.349523125 grams per avoirdupois ounce. That decimal does not terminate in the base-10 sense of common fractions, but it is an exact mathematical value derived from exact definitions. This calculator uses Big.js precision arithmetic with all 12 significant figures of the NIST constant.
The word “avoirdupois” comes from Old French meaning “goods of weight” and distinguished this weight system (used for everyday goods: food, coal, grain) from troy weight (used for precious metals) and apothecary weight (used for pharmaceuticals, now largely replaced by metric). In everyday US practice, you never need to say “avoirdupois ounce” because it is simply understood as the default. The abbreviation “oz” always refers to the avoirdupois ounce unless a context specifically indicates troy (often written “oz t” or “troy oz”).
Troy Ounce (Gold, Silver, and Precious Metals)
The troy ounce is the standard for precious metals worldwide, including gold, silver, platinum, and palladium. One troy ounce equals exactly 31.1034768 grams, which is approximately 10% heavier than the avoirdupois ounce (28.3495 g). This matters enormously in financial contexts: when a gold dealer quotes a price of $2,400 per ounce, they mean $2,400 per troy ounce, which is 31.1035 grams of gold. If you mistakenly assumed that “ounce” meant the common avoirdupois ounce (28.3495 grams), you would be paying $2,400 for about 8.9% less gold than you thought. At gold prices around $2,400 per troy ounce, that misunderstanding is worth about $214 per ounce of gold. The US gold and silver market is entirely denominated in troy ounces, and the Commodity Futures Trading Commission (CFTC) regulates futures contracts in troy ounces.
Troy weight comes from the French city of Troyes, a major medieval trading center where a specific weight standard was established. The troy pound (12 troy ounces) was adopted for English coinage in 1527 and has remained the standard for precious metals ever since, even after the avoirdupois system became dominant for general commerce. Note that a troy pound (12 troy oz) is lighter than an avoirdupois pound (16 avdp oz) despite the troy ounce being heavier than the avoirdupois ounce.
Fluid Ounce (Volume, Not Weight)
A US fluid ounce is a unit of volume, not weight. It equals exactly 29.5735295625 milliliters of volume. When you see a 12 fl oz soda can, that label is telling you the can holds about 355 mL of liquid, not that the liquid weighs a specific number of grams. The weight of 1 fluid ounce depends entirely on the density of the liquid. Water at standard conditions weighs about 29.57 grams per fluid ounce (because water’s density is approximately 1 g/mL). Honey is much denser and would weigh about 41 to 44 grams per fluid ounce. Vegetable oil is lighter than water and would weigh about 26 grams per fluid ounce. This calculator converts weight ounces (avoirdupois) to grams. It does not convert fluid ounces. If you have a liquid volume in fluid ounces, multiply by 29.5735 to get milliliters, then multiply by the liquid’s density in g/mL to get grams.
How This Ounces to Grams Calculator Delivers Exact Results
The conversion from avoirdupois ounces to grams uses the NIST-defined constant: 1 oz = 28.349523125 grams exactly. All calculations in this tool use Big.js arbitrary-precision arithmetic, meaning there is no floating-point rounding at any step. When you enter 8 ounces, the tool computes 8 times 28.349523125 in exact decimal arithmetic and returns 226.796185 grams, not 226.7961 or 226.80. For nutrition label work, medical dosing, food science, or international recipe conversion, that precision matters.
The reverse direction (grams to ounces) divides by 28.349523125. Since this does not produce a terminating decimal for most gram values, the result is shown with 6 decimal places of precision, which is more than sufficient for any practical food, nutrition, or laboratory use. The batch mode converts up to 20 values at once, outputting grams, ounces, kilograms, and pounds for each value, which is useful for converting an entire ingredient list or a product catalog from one unit system to another.
The 16 presets cover the most common US weight references: standard serving sizes from 0.5 oz to 32 oz, the 1.5 oz US standard liquor shot, the 3.5 oz value that corresponds to approximately 100 grams (useful for confirming nutrition label values), and a troy ounce preset so precious metal investors can quickly see the gram equivalent without confusion. Every preset includes a context note in the results panel explaining what US product or serving that weight corresponds to.
US FDA Nutrition Labeling and the Gram-Ounce Connection Every Consumer Should Know
If you read food labels in the United States, you are already using ounces and grams side by side without necessarily realizing it. The US Food and Drug Administration (FDA) requires nutrition facts panels on most packaged foods to list serving sizes in both household measures (cups, tablespoons, and ounces) and metric units (grams). This dual listing is mandated by FDA 21 CFR Part 101 and exists specifically so that consumers can compare products accurately regardless of which unit system they prefer.
The practical implication is that when a nutrition label says “Serving Size: 1 oz (28g),” that 28g is a rounded version of the exact 28.349523125 grams per ounce. The FDA allows rounding to the nearest gram on labels, which is why 1 oz shows as 28g rather than 28.350g. For most nutrition comparison purposes, 28g is fine. But for precision cooking, food science, supplement dosing, or dietary tracking apps, knowing the exact value matters. A diet that targets 100 grams of protein per day must account for the fact that 3.5 oz of chicken does not equal exactly 100g (3.5 times 28.349523125 equals 99.22 g, not 100 g). The difference is less than 1% but it accumulates across a full day of eating.
How Serving Sizes in Ounces and Grams Connect to Daily Nutrition Goals
The FDA’s 2020 updated nutrition facts label regulations, which took effect for most manufacturers by January 2020, revised many serving sizes to better reflect how Americans actually eat. Here are some common nutrition serving sizes in both ounces and their exact gram equivalents:
- Cereal (flake type): 1 oz = 28.350 g per serving
- Cheese: 1 oz = 28.350 g per serving (about 1 slice of American cheese)
- Nuts: 1 oz = 28.350 g per serving (about 23 almonds or 18 cashews)
- Lunch meat/deli slices: 2 oz = 56.699 g per serving
- Snack chips: 1 oz = 28.350 g per serving (typically about 28 chips depending on brand)
- Frozen meal protein portion: 3 oz = 85.049 g
- Greek yogurt single-serve cup: 5.3 oz = 150.242 g
- Standard can of tuna: 5 oz = 141.748 g drained weight
For fitness and athletic performance nutrition, where protein targets are often set in grams, this conversion is essential. A target of 150 grams of protein per day from whole food sources requires accurate ounce-to-gram conversions for planning and tracking. A 6 oz chicken breast contains approximately 170.097 grams of food, of which roughly 54 grams is protein (assuming a 32% protein content by cooked weight). Understanding the ounce-to-gram conversion lets you work accurately with both US recipe quantities (typically in ounces) and nutrition tracking apps (typically in grams).
Three Real-World US Ounce-to-Gram Conversion Examples
Baking a European Chocolate Cake Recipe: Converting Grams to US Ounces
A baker in Atlanta finds a highly rated Belgian chocolate cake recipe that lists all ingredients in grams. The recipe calls for 225 g of butter, 200 g of dark chocolate, and 150 g of all-purpose flour. The baker’s kitchen scale only measures in ounces, and they want to know the equivalent ounce weights for each ingredient.
Converting each: 225 g divided by 28.349523125 equals 7.937 oz of butter. 200 g divided by 28.349523125 equals 7.055 oz of dark chocolate. 150 g divided by 28.349523125 equals 5.291 oz of flour. Rounding to practical baking precision: 7.9 oz of butter, 7.1 oz of chocolate, and 5.3 oz of flour. A kitchen scale accurate to 0.1 oz can measure these quantities within the normal tolerance of home baking. For professional bakery scale-up, the gram values from the original recipe would be more reliable.
Gold Jewelry Purchase: Avoirdupois vs Troy Ounce Price Comparison
A customer at a Houston jewelry store is buying a 14-karat gold chain listed as weighing 2.5 oz on the product tag. The store quotes a gold content value based on spot price of $2,400 per troy ounce. The customer wants to know whether the “2.5 oz” on the product tag refers to avoirdupois or troy ounces, since that affects how much gold they are actually getting and whether the price is fair.
Jewelry weight tags almost always use avoirdupois ounces for the total piece weight (including the non-gold alloy metals). If the chain is listed as 2.5 oz (avoirdupois), that is 2.5 times 28.349523125 equals 70.874 grams total weight. At 14 karats (14/24 = 58.33% gold), the gold content is 70.874 times 0.5833 equals 41.343 grams of pure gold. Converting to troy ounces for pricing: 41.343 divided by 31.1034768 equals 1.330 troy ounces of gold. At $2,400 per troy ounce, the gold melt value is 1.330 times $2,400 equals $3,191. The retailer adds labor, design, and markup to that base value.
International Shipping: Declaring Package Weight in Grams for US Customs
A small e-commerce seller in Phoenix ships handmade candles internationally through USPS First Class Package International. Each candle weighs approximately 6.5 oz on their postal scale. The online customs form requires the declared weight in both US ounces and metric grams. The seller needs the exact gram value for the commercial invoice.
6.5 oz times 28.349523125 equals 184.272 grams. On the customs declaration, the seller lists 6.5 oz (184.3 g), rounding to one decimal place as is standard for commercial shipping documents. For calculating total shipping weight of a 12-candle order: 6.5 times 12 equals 78 oz, and 78 times 28.349523125 equals 2,211.26 grams, or approximately 2.211 kilograms. Most international shipping rates switch from per-ounce to per-kilogram calculation at certain weight thresholds, so knowing both the gram total and the kilogram equivalent helps select the most cost-effective shipping method.
Four Expert Tips for Cooking, Nutrition, and Precision Weight Conversions
28 Is Not Exact: The 0.35g You Lose Every Serving Matters at Scale
The most common kitchen shortcut is rounding 1 oz to 28 grams. That drops 0.349523125 grams per ounce, a 1.23% undercount. For a single serving, the difference is trivial. But in food manufacturing, if a product is labeled as containing 28 g per serving and the actual weight is 28.35 g, the manufacturer is giving away extra product on every unit. At 100,000 units per day, that is 35 kilograms of product lost to rounding. FDA nutrition label regulations allow grams to be rounded to the nearest gram, but production weights should be set to the exact NIST value for cost accuracy. Use this calculator’s full-precision output whenever you are scaling a recipe or production batch, and only round at the final display stage.
The 3.527 oz Shortcut for 100-Gram Conversions
One hundred grams divided by 28.349523125 equals 3.527396194958… ounces. So “3.527 oz” is the practical equivalent of “100 grams.” This number is worth memorizing because nutrition labels in many countries list values per 100 g, and US consumers often want to know how many ounces that is. Examples: a European yogurt with 10 g protein per 100 g serving contains 10 grams of protein in every 3.527 oz. A 5.3 oz Greek yogurt cup (the US standard) contains 5.3 divided by 3.527 equals about 1.5 servings worth of the 100-gram values. Keeping 3.527 oz = 100g in mind lets you quickly cross-reference international nutrition data with US serving sizes.
Kitchen Scales in Grams Beat Volume Measures for Baking Accuracy
US recipes traditionally use volume measures (cups, tablespoons), while European and professional baking recipes use weight in grams. A cup of all-purpose flour can vary from 120 g to 145 g depending on how you scoop it. That 25-gram range is nearly one full ounce of variation and directly affects the texture of baked goods. Professional bakers weigh all ingredients in grams for exactly this reason. If you bake from US recipes in ounces, use this calculator to confirm gram equivalents and verify your scale is reading correctly. A kitchen scale calibrated to 1 gram (0.035 oz) precision is sufficient for home baking. A scale accurate to 0.1 gram is needed for spice blends, coffee roasting, and pharmaceutical applications.
Fluid Ounces and Weight Ounces Are Not Interchangeable for Dense Liquids
Water is the only common liquid where fl oz and weight oz give approximately the same number. One US fluid ounce of water weighs about 29.57 grams, while one avoirdupois ounce is 28.35 grams. These are close but not equal. For dense liquids like honey (density about 1.42 g/mL), 1 fl oz weighs about 42 grams, which is 1.48 avoirdupois ounces. For lighter liquids like vegetable oil (density about 0.92 g/mL), 1 fl oz weighs about 27.4 grams, just under 1 avoirdupois ounce. If a recipe says “8 oz of cream” and you interpret that as 8 fl oz (volume), you get 236.6 mL of cream, which weighs about 244 grams. If you interpret it as 8 weight oz, you get 226.8 grams of cream. For most cooking, the difference is negligible. For precision formulation of cosmetics, pharmaceuticals, or food products, always clarify whether the ounce is a weight or volume measure.
How the Avoirdupois System Shapes US Retail, Shipping, and Commerce
The avoirdupois ounce is not just a cooking unit. It is the foundational weight unit that underlies a massive portion of US commercial infrastructure, from postal rates to retail product labeling to agricultural commodity contracts. Understanding how the ounce operates in these systems explains why accurate ounce-to-gram conversion is a business requirement, not just a kitchen convenience.
US Postal Service Weight Tiers and the Ounce
The United States Postal Service prices First Class Mail in one-ounce increments. A letter weighing exactly 1 oz pays the first-class letter rate. A letter weighing 1.01 oz to 2 oz pays the additional ounce rate. This means that a piece of mail weighing 28.4 grams costs less to mail than the same piece weighing 28.7 grams, even though the difference is less than a third of a gram. For direct mail marketers, catalog companies, and anyone mailing products at volume, calculating exact gram weights and their avoirdupois-ounce equivalents determines shipping costs directly. At 100,000 pieces per mailing, the difference between 28.3 g and 29.1 g per envelope could push every piece into the next ounce tier, adding a significant per-piece surcharge. This calculator’s full-precision output (28.349523125 g per oz) lets you set envelope and content weights to stay below each USPS ounce threshold without guessing.
For packages, USPS, UPS, and FedEx all have weight-based rate breaks at specific pound increments. Since 1 lb equals 453.59237 grams exactly, knowing the gram weight of a shipment lets you calculate exactly where it falls on the rate schedule. A package weighing 452 grams is under 1 lb (453.59 g) and gets the under-1-lb rate. A package weighing 454 grams is over 1 lb and moves to the next rate tier. At e-commerce scale, these marginal gram differences have real cost implications.
Agricultural Commodities and the USDA Pound-Ounce Framework
Most US agricultural commodities are traded in pounds and ounces at the consumer retail level, even though the underlying commodity contracts at the Chicago Board of Trade and other exchanges use metric tons. A retail beef label saying “Net Weight: 12 oz” means 12 times 28.349523125 equals 340.194 grams of beef. The USDA’s Agricultural Marketing Service (AMS) enforces accurate net weight labeling on all packaged meat, poultry, and produce under the Fair Packaging and Labeling Act. Scale certification requirements ensure that the 12 oz listed on a package is accurate to within allowable tolerances, typically 1 to 3 grams depending on the product weight class. Understanding that 1 oz equals 28.35 grams is essential for scale calibration, package fill weight setting, and compliance audits in any US food manufacturing facility.
Supplement Industry: Ounces on the Label, Milligrams Inside
The US dietary supplement industry presents an interesting dual-unit environment. The container label (the outside of the bottle or package) typically shows the net weight of the product in ounces (and sometimes grams) under FDA net weight labeling regulations. The supplement facts panel inside shows individual serving sizes and ingredient quantities in milligrams or micrograms. A 16 oz container of protein powder contains 453.59237 grams of product. If the serving size is 1 oz (28.35 g) and the container has 16 servings, the math works out cleanly. If a serving is 30 grams, the 453.59 g container yields 453.59 divided by 30 equals 15.12 servings, which the label rounds to “approximately 15 servings.” For dietary supplement formulators, setting ingredient levels at specific milligram-per-gram concentrations requires knowing the exact gram-to-ounce factor to verify that the container weight matches the serving count on the label.
Ounce-to-Gram Conversions in US Medical and Clinical Settings
While US pharmaceutical dosing is entirely in metric units (milligrams, grams, milliliters), patient-reported body weights in US clinical settings are still often in pounds and ounces, particularly for infants and young children. A newborn weighed at 7 lb 4 oz (seven pounds and four ounces) has a weight of 7 times 453.59237 plus 4 times 28.349523125 equals 3175.147 plus 113.398 equals 3,288.545 grams, or 3.289 kilograms. Drug dosing for pediatric patients in US hospitals uses weight-based protocols in mg/kg, so accurate pound-ounce-to-gram conversion is a clinical requirement. The Joint Commission and American Academy of Pediatrics both recommend recording pediatric weights in kilograms to reduce dosing errors, but the transition from pounds-and-ounces to kilograms in US hospitals is still ongoing in many facilities.
Quick Reference: Ounces to Grams Conversion Table for Common US Weights
| Ounces (oz) | Grams (g) | Kilograms (kg) | Milligrams (mg) | US Context |
|---|---|---|---|---|
| 0.5 oz | 14.175 | 0.014175 | 14,175 | Half ounce / baking measure |
| 1 oz | 28.350 | 0.028350 | 28,350 | Standard serving / 1 slice cheese |
| 1.5 oz | 42.524 | 0.042524 | 42,524 | US standard liquor shot |
| 2 oz | 56.699 | 0.056699 | 56,699 | Deli meat serving |
| 3 oz | 85.049 | 0.085049 | 85,049 | Palm-size protein portion |
| 3.527 oz | 100.000 | 0.100000 | 100,000 | Exactly 100 grams (intl. serving ref.) |
| 4 oz | 113.398 | 0.113398 | 113,398 | Quarter pound / 4-oz burger |
| 6 oz | 170.097 | 0.170097 | 170,097 | Greek yogurt / chicken breast |
| 8 oz | 226.796 | 0.226796 | 226,796 | Half pound / cup of flour |
| 12 oz | 340.194 | 0.340194 | 340,194 | Soda can / beer can |
| 16 oz | 453.592 | 0.453592 | 453,592 | 1 pound (exactly) |
| 32 oz | 907.185 | 0.907185 | 907,185 | 2 pounds |
Frequently Asked Questions About Ounces and Grams
One avoirdupois ounce equals exactly 28.349523125 grams. This is derived from the 1959 International Yard and Pound Agreement, which defined 1 pound as exactly 453.59237 grams, and since 1 pound equals 16 ounces, 1 ounce equals 453.59237 divided by 16 equals 28.349523125 grams. This is an exact mathematical relationship. Common rounding to 28 grams introduces a 1.23% error per ounce, which is fine for casual cooking but not for food manufacturing, pharmaceutical dosing, or international commercial transactions.
The rounded value of 28 grams is an approximation. The exact value is 28.349523125 grams per avoirdupois ounce. Rounding to 28 drops 0.349523125 grams per ounce. That is a 1.23% undercount. For single-serving nutrition estimates, rounding to 28 g is acceptable. For recipes scaled to large batches, production line settings, or nutritional database entries, always use the full 28.349523125 value. US FDA nutrition label regulations allow rounding to the nearest gram, which is why labels show 28 g for 1 oz. The exact NIST value is the one used in this calculator.
The avoirdupois ounce equals 28.349523125 grams and is the standard for everyday goods: food, body weight, postal packages, and general commerce. The troy ounce equals 31.1034768 grams (about 9.7% heavier) and is used exclusively for precious metals (gold, silver, platinum, palladium). When you buy gold or silver, prices are always quoted in troy ounces. When you weigh food or body weight, you use avoirdupois ounces. Mixing them up in a precious metals transaction is costly: if you think you bought “2 ounces of gold” in avoirdupois terms but received 2 troy ounces, you received 62.207 g instead of 56.699 g, meaning you got more gold than you calculated. The reverse mistake, paying for 2 troy oz but only getting 2 avdp oz, costs you 62.207 minus 56.699 equals 5.508 grams of gold per transaction.
100 grams equals 100 divided by 28.349523125 equals 3.527396194… avoirdupois ounces. The practical value to remember is 3.527 oz = 100 g. This is useful because many international food labels list nutritional content per 100 grams, and US consumers need to convert that to ounces to understand the portion size. Example: if a European chocolate bar label says 15 g fat per 100 g, and the bar weighs 3.527 oz (100 g), the whole bar contains 15 g of fat. If the bar weighs 1.76 oz (50 g), it contains 7.5 g of fat for the whole bar.
One avoirdupois pound equals exactly 453.59237 grams. This is the exact definition from the 1959 International Yard and Pound Agreement. Since 1 pound equals 16 ounces and 1 ounce equals 28.349523125 grams, you can verify: 16 times 28.349523125 equals 453.59237 grams. Common rounding: 1 lb is approximately 454 grams. One kilogram equals 1,000 grams, so 1 kg equals 1,000 divided by 453.59237 equals 2.20462 pounds. For cooking: 1 lb of butter (4 sticks) equals 453.59 grams. 1 lb of flour varies by how it is packed but is defined as 16 oz by weight.
Divide grams by 28.349523125 to get avoirdupois ounces. Or equivalently, multiply grams by 0.03527396194… Examples: 200 g divided by 28.349523125 equals 7.055 oz. 500 g divided by 28.349523125 equals 17.637 oz. 1000 g (1 kg) divided by 28.349523125 equals 35.274 oz (2.205 lb). This calculator handles the reverse direction with full precision. Select “Grams to Ounces” in the direction dropdown, enter your gram value, and the result shows avoirdupois ounces, kilograms, milligrams, and pounds.
No. A US fluid ounce (fl oz) is a unit of volume equal to exactly 29.5735295625 milliliters. An avoirdupois ounce (oz) is a unit of weight equal to 28.349523125 grams. They are different units measuring different properties. For water at standard conditions (density approximately 1 g/mL), the values happen to be close: 1 fl oz of water weighs about 29.57 grams, which is close to but not the same as 1 avoirdupois ounce (28.35 grams). For denser liquids like honey or lighter liquids like alcohol, the difference between fl oz by volume and oz by weight can be 20% or more. This calculator converts avoirdupois weight ounces only. For fluid ounce to milliliter conversions, use a volume converter.
The label “12 oz” on a US soda can refers to 12 US fluid ounces of liquid, which equals 12 times 29.5735295625 equals 354.882 milliliters (rounded to 355 mL). The total weight of the can including the aluminum and liquid is typically around 370 to 390 grams depending on the brand and carbonation level. The liquid itself (typically water with syrup) weighs approximately 370 grams. In terms of the fluid ounce converted to grams: 12 fl oz of soda weighs approximately 12 times 29.57 grams per mL times 1.04 g/mL (the density of carbonated soda is slightly greater than water) equals about 368 grams. The weight ounce equivalent of 12 fl oz of soda is 368 divided by 28.3495 equals about 13.0 avoirdupois ounces of liquid (heavier than 12 oz by weight).
On a US FDA nutrition label, 1 oz is listed as 28 grams (rounded to the nearest gram per FDA regulations). The exact value is 28.349523125 grams, but labels round to whole grams for readability. This means a product labeled “1 oz (28g)” actually contains 28.349523125 grams, and the nutrition values are calculated for that exact weight, not for a rounded 28 grams. For calorie and macronutrient tracking, using 28 g instead of 28.35 g introduces less than 1.25% error per serving, which is within normal daily dietary variation and acceptable for personal health tracking. For clinical nutrition research or food safety compliance, use the full NIST value.
4 avoirdupois ounces equals 4 times 28.349523125 equals 113.398093 grams. The “Quarter Pounder” at McDonald’s gets its name from the pre-cooked patty weight of 4 oz (one quarter pound or 113.4 grams). After cooking, the patty loses moisture and weighs approximately 2.9 oz (82 grams). When US butchers and grocery stores label ground beef as “1/4 lb,” they mean exactly 4 avoirdupois ounces = 113.398 grams. For fitness tracking, 4 oz of lean ground beef (90% lean) contains approximately 25 to 28 grams of protein and about 150 to 170 calories, varying by specific fat content and cooking method.
8 avoirdupois ounces equals 8 times 28.349523125 equals 226.796185 grams, commonly rounded to 226.8 g or 227 g. Eight ounces is also one-half pound. In cooking, 8 oz is a very common quantity: a block of cream cheese is typically 8 oz (226.8 g), a standard mozzarella ball is 8 oz (226.8 g), and many US recipes call for 8 oz of various ingredients ranging from sour cream to pasta to shredded cheese. For international recipes where the quantity is in grams, 225 g is the nearest round number and a common European recipe quantity that is close to the US 8-oz standard.
One troy ounce equals exactly 31.1034768 grams. Gold, silver, platinum, and all precious metal prices worldwide are quoted per troy ounce. When you see a gold spot price of $2,400 per ounce, it means $2,400 per 31.1035 grams of gold. This is not the same as an avoirdupois ounce (28.3495 grams). The troy ounce is about 9.7% heavier than the avoirdupois ounce. A 1-oz gold bullion coin such as the American Gold Eagle contains exactly 1 troy ounce (31.1035 grams) of gold, even though the total coin weight including the alloy metals is slightly heavier. The US Mint guarantees the gold content of American Gold Eagle coins in troy ounces.
The United States inherited the avoirdupois system from British colonial measurement traditions and never underwent the wholesale metric adoption that most other countries completed in the 19th and 20th centuries. The Metric Conversion Act of 1975 made metric “the preferred system of weights and measures for United States trade and commerce” but did not mandate metric use for consumers, which left the customary system in place for everyday US life. Today the US is one of three countries in the world (along with Liberia and Myanmar) that has not fully adopted the metric system for everyday use. The FDA requires metric units on nutrition labels alongside customary units, and US pharmaceutical dosing is entirely in metric (mg, g, mL). But food retail, recipe writing, postal rates, and everyday consumer products remain primarily in ounces and pounds.
5 avoirdupois ounces equals 5 times 28.349523125 equals 141.747615625 grams, commonly rounded to 141.75 g. Common US references for 5 oz: a standard restaurant wine pour is 5 fl oz (about 148 mL), but a 5-oz weight of wine would be 141.75 grams. A standard 5-oz can of tuna (drained) weighs 141.75 grams. A medium-sized chicken breast is typically 5 to 6 oz (142 to 170 grams). In silver investing, a 5-oz silver bar weighs 5 troy ounces equals 155.517 grams, which is slightly more than 5 avoirdupois ounces. Always confirm which ounce type applies in precious metals contexts.
This calculator uses the exact NIST-defined value of 28.349523125 grams per avoirdupois ounce and Big.js arbitrary-precision arithmetic with no floating-point rounding. Results are mathematically exact to the precision of the input. For most pharmaceutical applications, metric units (milligrams and grams) are the standard in the US, and avoirdupois ounces are rarely used in drug dosing. If you encounter a pharmaceutical weight in ounces, this tool converts accurately. However, for any clinical, compounding, or dispensing application, dosage calculations must be verified by a licensed pharmacist or healthcare professional. This tool is not a substitute for professional pharmaceutical guidance.
16 avoirdupois ounces equals exactly 453.59237 grams. This is the internationally defined value for 1 US pound. It is not a rounded approximation; 453.59237 grams is the exact legal definition. One pound equals 453.59237 grams because the International Yard and Pound Agreement of 1959 defined the US and UK avoirdupois pound as exactly 453.59237 grams, a value that aligned the two countries’ measurement systems with the metric system. This means 1 kg equals 1000 / 453.59237 equals 2.20462262… pounds, and 1 lb equals 453.59237 / 1000 equals 0.45359237 kg. These are exact relationships, not approximations.
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Legal Disclaimer and Editorial Transparency
This ounces to grams converter is provided for educational and general informational purposes only. All conversions use the exact internationally defined value: 1 avoirdupois ounce = 28.349523125 grams exactly, derived from 1 lb = 453.59237 g as established by the 1959 International Yard and Pound Agreement and documented in NIST Special Publication 811. The troy ounce reference value of 31.1034768 grams is from the international troy system. US fluid ounce (29.5735295625 mL) is a volume unit and is not converted by this tool. Nutrition label references comply with FDA 21 CFR Part 101. Precious metals pricing information is for illustrative purposes only and does not constitute investment advice. Pharmaceutical calculations require verification by a licensed healthcare professional. Content written and reviewed by the USCalculators.com editorial team.