🛢️ 1 US Gallon = 128 fl oz (UK Gallon = 153.72 US fl oz!)

Gallons to Ounces Converter: US vs UK Gallon Gap Explained, Pool Chemical Dosing, Fuel Tank Sizes, and Why 55-Gallon Drums Are Not Equal Between Countries

Built and reviewed by David (MBA Finance) · Updated August 2026

1 US liquid gallon = 128 US fluid ounces (exact). UK imperial gallon = 160 UK fl oz = 153.72 US fl oz = 20.09% more than US gallon. Half-barrel keg = 15.5 US gal = 1,984 fl oz = 165 beers. 55-gal drum = 7,040 US fl oz = 208.20 L. Pool: length x width x avg depth (ft) x 7.48 = gallons. Four App Decoder modes: pool dosing, fuel tanks, container sizes, US vs UK gallon. 16 presets from 12 fl oz can through 100 gallons. Free PDF. WhatsApp share.

1 US gal = 128 fl oz (exact) UK gal = 153.72 US fl oz (20% more) Half-barrel keg = 15.5 gal = 1,984 fl oz Pool: L x W x depth x 7.48 = gal 55-gal drum = 7,040 fl oz = 208 L Batch up to 20 Values

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Gallons to Fl Oz

US Gallons

gal

Common Presets

1 US gal = 128 fl oz (exact). UK gal = 153.72 US fl oz (20.09% more). 5 gal=640 fl oz. 55 gal=7,040 fl oz. Half-barrel keg=15.5 gal=1,984 fl oz. Pool: L x W x depth(ft) x 7.48=gallons. 1 US gal=3,785.41 mL=3.785 L=4 qt=8 pt=16 cups.

Conversion Result

0 US fl oz

0Liters

0US Quarts

0US Pints

Formula and Reference

The 20% US vs UK Gallon Gap, the US Dry Gallon Mystery, and Why 1 US Gallon = 128 fl oz Is the Only Number You Need for American Everyday Life

The US liquid gallon is defined as exactly 128 US fluid ounces, 4 US quarts, 8 US pints, 16 US cups, 256 US tablespoons, and 768 US teaspoons. In metric: 1 US gallon = 3,785.411784 mL = 3.785411784 liters. This exact value comes from the 1893 Mendenhall Order, which defined US units from the metric system, and NIST Handbook 44. Every gas pump, water jug, paint can, pool chemical label, and appliance spec in the United States uses the US liquid gallon = 128 fl oz.

The UK imperial gallon is different: 1 UK gallon = 4.54609 liters = 4,546.09 mL = 160 UK fluid ounces = 153.72 US fluid ounces. The UK gallon is 20.09% larger than the US gallon. This gap is widely misunderstood and creates real confusion when American readers encounter British car reviews (which report MPG in UK gallons, appearing better than US MPG), British recipe books (which state “gallons” of water or stock), or British appliance manuals. A British car rated at “50 MPG” in the UK uses 50 miles per UK gallon (4.546 L), which equates to about 41.6 MPG in the US standard. The UK also uses UK pints (20 UK fl oz = 568 mL) vs US pints (16 fl oz = 473 mL), a 20% gap that makes a UK “pint of beer” larger than a US “pint of beer.” NIST at NIST.gov. NIST Handbook 44 at NIST.gov/pml.

The US dry gallon (= 4 US dry quarts = 4.40488475 liters = 268.8025 US fl oz) is a separate measure used only for agricultural dry goods: bushels, pecks, dry quarts of produce like berries, grain, and dried beans. It is 40.6% larger than the US liquid gallon. If you ever see a bushel measurement, the connection is: 1 US bushel = 8 US dry gallons. All consumer products in the US, including every product at a grocery store, hardware store, and gas station, use the US liquid gallon of 128 fl oz. The dry gallon is a legacy agricultural measure you will not encounter in everyday consumer or commercial transactions.

1 US gal = 128 fl oz Exact, by definition. = 4 qt = 8 pt = 16 cups = 256 tbsp = 3,785.41 mL. Source: NIST Handbook 44.

UK gal = 153.72 US fl oz 1 UK gallon = 4,546.09 mL = 160 UK fl oz = 1.20095 US gallons. 20.09% more than US gallon. Matters in car specs, British recipes.

55 US gal = 7,040 fl oz Standard US drum = 208.20 L. UK 55-gal drum = 250.03 L (more). Half-barrel keg = 15.5 US gal = 1,984 fl oz = 165 beers.

How This Four-Mode Gallons to Ounces Converter Works for Pool Owners, Drivers, Home Brewers, and International Buyers

Mode 1: Single Gallons to US Fl Oz

Enter any US gallon value. Output: US fluid ounces (exact: x128), milliliters, liters, US quarts, pints, cups, and a UK gallon cross-reference. 16 presets from a 12 fl oz can (0.09375 US gal) through 100 gallons. The context note explains common applications: aquarium sizes, fuel tank ranges, keg sizes, gas can standards, and drum equivalents. Bar chart compares your input against standard reference sizes.

Mode 2: App Decoder

Four categories: Pool Chemical Dosing (common US pool sizes from 8,000 to 30,000 gallons with shock treatment reference), Vehicle Fuel Tank Sizes (Honda Civic 12 gal through Ford F-150 23 gal with MPG range estimates), Common US Container Sizes (12 fl oz can through 5-gallon jug decoded), and US vs UK Gallon comparison (1 through 55 gallons showing the gap). Enter your gallon value to see it highlighted against the reference table.

Mode 3: Batch Gallons to Fl Oz

Enter up to 20 US gallon values, one per line. Output: a table with US fl oz, liters, US quarts, and US pints for each. Useful for a pool supply dealer creating a dosing reference card, a fleet manager comparing fuel tank capacities, or a homebrewer planning multiple batch sizes.

Complete Gallons to Fluid Ounces Reference: Container Hierarchy, Keg Sizes, Drum Standards, and US vs UK Volume at Every Scale

US Gallons	US Fl Oz	Liters	US Quarts	US Pints	Common Reference
0.09375	12 fl oz	0.355 L	0.375 qt	0.75 pt	Standard US soda/beer can. 24-pack = 288 fl oz = 2.25 US gal.
0.125	16 fl oz	0.473 L	0.500 qt	1.00 pt	1 US pint. Sour cream, US beer pint glass. UK pint = 20 UK fl oz = 0.568 L (25% larger).
0.25	32 fl oz	0.946 L	1.000 qt	2.00 pt	1 US quart. Motor oil, small paint, deli soup. Nearly 1 liter (946 mL).
0.5	64 fl oz	1.893 L	2.000 qt	4.00 pt	Half gallon. OJ carton, half-gallon milk, ice cream (watch for shrinkflation to 48 oz).
1	128 fl oz	3.785 L	4.000 qt	8.00 pt	1 US gallon. Milk jug, paint can, water jug. UK gallon = 153.72 US fl oz (20.09% more).
1.5	192 fl oz	5.678 L	6.000 qt	12.00 pt	1.5 US gallons. Larger paint project. 192 fl oz = 6 US quarts.
2	256 fl oz	7.571 L	8.000 qt	16.00 pt	2 US gallons = 256 fl oz. Large water container, detergent jug.
2.5	320 fl oz	9.464 L	10.00 qt	20.00 pt	Small gas can (Scepter, No-Spill standard). 2.5 gal = 9.46 L.
5	640 fl oz	18.927 L	20.00 qt	40.00 pt	Standard gas can, 5-gal water jug, homebrew batch size, 5-gal bucket. 18.93 L.
7.75	992 fl oz	29.337 L	31.00 qt	62.00 pt	Quarter-barrel keg = 7.75 US gal = 992 fl oz = 82 12-oz beers.
15.5	1,984 fl oz	58.673 L	62.00 qt	124.0 pt	Half-barrel keg = 15.5 US gal = 1,984 fl oz = 165 12-oz beers = 124 US pints.
20	2,560 fl oz	75.708 L	80.00 qt	160.0 pt	20-gallon aquarium. Average car fuel tank. 20 US gal = 16.65 UK gal.
30	3,840 fl oz	113.562 L	120.0 qt	240.0 pt	Large contractor trash can. 55-gal drum half. Pool: 30,000 gal = large inground.
55	7,040 fl oz	208.198 L	220.0 qt	440.0 pt	Standard US 55-gal steel drum = 7,040 fl oz = 208.20 L. UK 55-gal drum = 250.03 L.
1 (ref)	128 fl oz	3.785411784 L	4 qt	8 pt	Exact: 1 US liquid gal = 128 US fl oz = 3,785.411784 mL. Source: NIST Handbook 44.

Exact: 1 US liquid gallon = 128 US fl oz = 3,785.411784 mL = 3.785411784 L. Source: NIST.gov. UK gallon: 1 UK gal = 4.54609 L = 160 UK fl oz = 153.72 US fl oz (20.09% larger than US gallon). TTB spirits: TTB.gov. EPA: EPA.gov. Pool chemical safety: CDC.gov/healthywater/swimming.

Pool Size in Gallons: Estimating Volume by Shape

Pool Shape	Formula	Example	Result
Rectangular	L x W x Avg Depth (ft) x 7.48052	14 x 28 x 5 ft avg depth	14,651 gallons
Round (above-ground)	Pi x r^2 x Depth (ft) x 7.48052	15 ft diameter, 4 ft deep	5,301 gallons
Oval	L x W x 0.785 x Depth (ft) x 7.48052	12 x 24 x 4 ft avg	8,506 gallons
Irregular/Kidney	Avg L x Avg W x 0.45 x Depth (ft) x 7.48052	estimate	Use as approximation
Average depth	(Shallow end depth + Deep end depth) / 2	3 ft shallow, 7 ft deep	5 ft avg depth
Shock treatment	Pool gallons / 10,000 x 1 lb Cal-Hypo (65%)	20,000 gal pool	2 lbs Cal-Hypo

Pool volume formulas from CDC.gov/healthywater/swimming. Pool chemical dosing on label; always follow manufacturer directions and NSF/ANSI 50. EPA pool chemical safety at EPA.gov. Always test water chemistry with a kit before adding chemicals. NIST measurement at NIST.gov.

Three Real US Examples: A Kansas Pool Owner Calculating Shock Treatment, a Dallas F-150 Driver Planning a Road Trip, and a Seattle Home Brewer Scaling a 5-Gallon Batch

Example 1: A Lenexa, Kansas Pool Owner Calculating Shock Treatment for a 20,000-Gallon Inground Pool After a Heavy Rain Event

Pool: 14 x 28 ft rectangle, 5 ft avg depth. Volume: 14 x 28 x 5 x 7.48052 = 14,651 US gal (or measured at 20,000 gal for a larger pool). 20,000 US gal = 2,560,000 US fl oz. Shock: 2 lbs calcium hypochlorite (65%) for 20,000 gal. pH must be 7.4-7.6 before shocking. CDC recommends free chlorine 1-3 ppm for residential pools.

Lenexa, Kansas homeowner and pool owner Brad has a 20,000-gallon inground rectangular pool. After a heavy Midwestern thunderstorm washed debris and bacteria into the pool, he needs to shock the pool to restore safe water chemistry. His pool supply store sells shock treatment in 1-lb bags, each rated for 10,000 gallons. He needs to calculate the total pool volume in both gallons and fluid ounces, then determine the correct shock dose.

Pool volume: 14 x 28 ft x 5 ft average depth x 7.48052 = 14,651 US gallons (Brad’s actual pool). If the pool is 20,000 gallons as stated: 20,000 US gal = 2,560,000 US fl oz = 75,708.24 L = 75.71 metric tons of water. Shock treatment: 20,000 gal / 10,000 gal per lb = 2 lbs calcium hypochlorite (65%). Brad should add 2 x 1-lb bags at dusk (UV degrades chlorine), run the pump overnight, and retest in the morning. The pool holds 75,708 liters, so the 2 lbs of Cal-Hypo raises free chlorine approximately 5-7 ppm above current levels. Target: 1-3 ppm free chlorine for safe swimming. Pre-shock: always test pH (7.4-7.6 ideal), alkalinity (80-120 ppm), and cyanuric acid (30-50 ppm). CDC pool safety at CDC.gov/healthywater/swimming. NSF/ANSI 50 at NSF.org. EPA pool chemicals at EPA.gov.

Example 2: A Dallas F-150 Driver Planning a Round Trip to Galveston and Calculating Fill-Up Cost and Range

2024 Ford F-150 (3.5L EcoBoost): 23 US gal tank = 2,944 US fl oz = 87.06 L. Highway MPG: 24 MPG. Tank range: 23 x 24 = 552 miles per tank. Dallas to Galveston: 280 miles one-way = 560 miles round trip. Fuel needed: 560 / 24 = 23.3 gallons = nearly exactly 1 full tank. At $3.50/gal: $81.55 round trip fuel cost.

Dallas marketing manager and F-150 owner Keisha is planning a weekend trip from Dallas to Galveston Island (280 miles each way). She wants to calculate exactly how much fuel she will need and what it will cost, and whether she can make it on one tank or needs a stop on the way back.

2024 Ford F-150 3.5L EcoBoost: 23 US gallons = 2,944 US fl oz = 87.06 L. EPA highway rating: 24 MPG. Range on full tank: 23 gal x 24 MPG = 552 miles. Round trip: 560 miles. Fuel for round trip: 560 / 24 = 23.33 gallons = 2,987 fl oz. With a full 23-gal tank: she will arrive back in Dallas needing about 0.33 gallons (42 fl oz) more than one tank provides. She should plan a fuel stop in Houston on the way back (or leave Dallas with a full tank and fill up once in the Houston area). Cost: 23.33 gal x $3.50 = $81.67 total fuel cost. Note: 23 US gallons = 87.06 liters. UK equivalent: 23 US gal = 23 / 1.20095 = 19.15 UK gallons (relevant if she looks up her truck’s specs on a UK automotive site). EPA fuel economy at FuelEconomy.gov. DOE transportation energy at Energy.gov/transportation.

Example 3: A Seattle Home Brewer Converting a 5-Gallon Belgian Tripel Recipe to Liters for a German Brewing Partner

5 US gal homebrew batch = 640 US fl oz = 18.927 L = 18,927 mL. Belgian Tripel grain bill: 14 lbs Pilsner malt per 5 US gal. Hop addition: 1.5 oz Saaz at 60 min. Strike water: 4.5 US gal = 576 fl oz = 17.034 L. Sparge water: 3 US gal = 384 fl oz = 11.356 L. Total grain water: 7.5 US gal = 960 fl oz = 28.391 L. German batch equivalent: 20 L = 5.283 US gal.

Seattle software engineer and homebrewer Marcus is collaborating with a brewing partner in Hamburg, Germany on a Belgian Tripel recipe. His recipe is in US gallons, and his German partner works in liters. They need to convert the entire recipe to share it.

Converting Marcus’s 5-US-gallon batch to liters: 5 US gal = 18.927 L. Strike water: 4.5 US gal = 17.034 L. Sparge water: 3 US gal = 11.356 L. Total brewing water: 7.5 US gal = 28.391 L. His German partner’s 20L batch (a common German homebrew size): 20 L / 3.785411784 = 5.283 US gallons. Scaling Marcus’s recipe to 20 L: multiply all ingredients by 20/18.927 = 1.057. Grain bill: 14 lbs x 1.057 = 14.8 lbs = 6.71 kg. Hops: 1.5 oz x 1.057 = 1.585 oz = 44.93 g. Standard homebrew yield: 5 US gal finished beer = about 640 fl oz = 54 twelve-ounce bottles or 40 US pint glasses (16 fl oz each). A half-barrel keg = 15.5 US gal = 3.1 x 5-gallon batches. TTB homebrew regulations at TTB.gov. American Homebrewers Association at HomebrewersAssociation.org.

Five Expert Tips: UK Gallon Confusion in Car Specs, Pool Volume Estimation, the Keg Math Every Bar Manager Should Know, Drum Safety, and Why Your Appliance Manual Might List UK Gallons

Tip 1: How to Convert UK MPG to US MPG When Reading British Car Reviews

UK car reviews report fuel economy in miles per UK imperial gallon (4.54609 L). US car reviews report miles per US liquid gallon (3.785411784 L). To convert UK MPG to US MPG: multiply by 3.785411784 / 4.54609 = multiply by 0.8326. Examples: UK “50 MPG” x 0.8326 = 41.6 US MPG. UK “60 MPG” = 49.9 US MPG. UK “40 MPG” = 33.3 US MPG. This is why small European cars imported or reviewed in the UK appear dramatically more efficient than their US equivalents on paper. A Honda Jazz rated 62.8 MPG in the UK equals 52.3 US MPG. Also: Canadian fuel economy is reported in L/100km (liters per 100 kilometers), a completely different metric. To convert US MPG to L/100km: L/100km = 235.215 / US MPG. 30 US MPG = 7.84 L/100km. EPA fuel economy data at FuelEconomy.gov. DOE energy data at Energy.gov.

Tip 2: The Easiest Way to Estimate Your Swimming Pool Volume in Gallons

For a rectangular or free-form pool: measure length, width, and average depth in feet. Average depth = (shallow end + deep end) divided by 2. Multiply length x width x average depth x 7.48052 = US gallons. For a 14 x 28 ft pool with 3 ft shallow, 7 ft deep: average depth = (3+7)/2 = 5 ft. Volume: 14 x 28 x 5 x 7.48052 = 14,651 US gallons. For a round above-ground pool: pi x (diameter/2)^2 x depth x 7.48052. A 15 ft round pool, 4 ft deep: 3.14159 x 56.25 x 4 x 7.48052 = 5,301 US gallons. Common rule of thumb: 8 gallons per cubic foot of water volume (actually 7.48052, so 8 is a slight overestimate). Key pool sizes for chemical reference: 10,000 gal = standard above-ground. 20,000 gal = average inground. 30,000 gal = large inground or commercial. Pool volumes are also stamped on some pool manufacturer documentation. CDC pool chemistry at CDC.gov/healthywater/swimming.

Tip 3: Keg Math Every Home Bartender and Bar Manager Should Know

US keg sizes in gallons and fluid ounces: Full barrel (rare): 31 US gal = 3,968 fl oz = 330 twelve-oz beers. Half-barrel (standard US bar keg): 15.5 US gal = 1,984 fl oz = 165 twelve-oz beers = 124 US pints = 82 US pints of 24 oz. Quarter-barrel (pony keg): 7.75 US gal = 992 fl oz = 82 twelve-oz beers. Sixth-barrel (torpedoes, “sixtel”): 5.16 US gal = 660 fl oz = 55 twelve-oz beers. Cornelius keg (homebrew “corny keg”): 5 US gal = 640 fl oz = 53 twelve-oz beers. Note: a “50-liter keg” (European standard) = 50 L = 13.21 US gal = 1,690 US fl oz = 140 twelve-oz beers. For events: plan approximately 2 beers per person per hour. A half-barrel (15.5 gal) serves about 82 people for a one-hour party at 2 beers each. TTB at TTB.gov. NIAAA at NIAAA.nih.gov.

Tip 4: Why Appliance Manuals Sometimes List UK Gallons and How to Convert to US Gallons

Imported appliances, boat documentation, British motorcycles, and European commercial kitchen equipment may list tank or container sizes in UK imperial gallons (even when sold in the US, if the documentation was not localized). A motorcycle manual listing “3.4 gallon fuel tank” for a British bike may mean 3.4 UK gallons = 3.4 x 153.72 US fl oz = 522.6 US fl oz = 4.08 US gallons. A British steam cleaner listing “2-gallon water tank” may mean 2 UK gal = 9.09 L = 2.40 US gallons. To convert UK gallons to US gallons: multiply by 1.20095. To convert US gallons to UK gallons: divide by 1.20095. For comparison: 1 US gallon = 0.83267 UK gallons. Always check whether a British or European product’s manual uses US gallons or UK gallons before purchasing a replacement part, tank, or accessory sized in “gallons.” NIST weights and measures at NIST.gov/pml/weights-and-measures.

Tip 5: The 55-Gallon Drum: Why a US Drum and a UK Drum of the Same Name Hold Very Different Volumes

The US standard 55-gallon steel drum (also called a 55-gallon barrel) holds 55 US liquid gallons = 7,040 US fluid ounces = 208.197 liters. This is the basis for industrial bulk chemical pricing (per 55-gallon drum), petroleum product measurement (though oil uses 42-US-gallon barrels), and waste disposal regulations. If a supplier in the UK or Canada quotes a “55-gallon drum,” they typically mean 55 UK imperial gallons = 250.035 liters = 8,800 UK fl oz = 8,454.72 US fl oz = 66.052 US gallons. The gap: UK 55-gallon drum holds 41.84 more liters (about 11 US gallons more) than a US 55-gallon drum. For chemical purchasing: always confirm whether the quantity is in US gallons or UK gallons. US petroleum barrel = 42 US gallons = 5,376 fl oz = 158.987 L (NOT 55 gallons). Industrial drums: EPA drum regulations at EPA.gov/rcra. DOT drum shipping at Transportation.gov.

Quick Reference: Common US Gallon Values Converted to Fluid Ounces

US Gallons	US Fl Oz	Liters	UK Gal Equiv	Reference	Source
0.125 gal	16 fl oz	0.473 L	0.104 UK gal	1 US pint. Sour cream, beer pint glass.	NIST.gov.
0.25 gal	32 fl oz	0.946 L	0.208 UK gal	1 US quart. Motor oil, deli soup. Nearly 1 L.	NIST.gov.
0.5 gal	64 fl oz	1.893 L	0.416 UK gal	Half gallon. OJ, milk, ice cream jug.	NIST.gov.
1 gal	128 fl oz	3.785 L	0.833 UK gal	US gallon. Milk jug, paint, water. UK gal = 153.72 US fl oz.	NIST.gov.
5 gal	640 fl oz	18.927 L	4.164 UK gal	Gas can, water jug, homebrew batch, 5-gal bucket.	NIST.gov.
7.75 gal	992 fl oz	29.337 L	6.454 UK gal	Quarter-barrel keg = 82 12-oz beers.	NIST.gov. TTB.gov.
15.5 gal	1,984 fl oz	58.673 L	12.908 UK gal	Half-barrel keg = 165 12-oz beers = 124 US pints.	NIST.gov. TTB.gov.
42 gal	5,376 fl oz	158.987 L	34.972 UK gal	US petroleum barrel. Oil industry standard. NOT a 55-gal drum.	NIST.gov. EIA.gov.
55 gal	7,040 fl oz	208.198 L	45.800 UK gal	Standard US 55-gal drum = 208.20 L. UK 55-gal drum = 250.03 L.	NIST.gov. EPA.gov.
1 gal (ref)	128 fl oz	3.785411784 L	0.832674 UK gal	Exact: 1 US liquid gal = 128 US fl oz = 3,785.411784 mL. NIST Handbook 44.	NIST.gov.

Exact: 1 US liquid gallon = 128 US fl oz = 3,785.411784 mL. Source: NIST.gov NIST Handbook 44. UK gallon: 4.54609 L per UK definition. Pool: CDC.gov/healthywater/swimming. TTB: TTB.gov. EPA: EPA.gov. DOE: Energy.gov. Fuel economy: FuelEconomy.gov.

Frequently Asked Questions: Gallons to Ounces

1 US liquid gallon = 128 US fluid ounces exactly. This is by definition of the US customary system. 1 US gallon = 4 quarts = 8 pints = 16 cups = 3,785.411784 mL. Source: NIST Handbook 44, NIST.gov.

Half US gallon = 0.5 x 128 = 64 US fluid ounces. 64 fl oz = 2 quarts = 4 pints = 8 cups = 1,892.706 mL = 1.893 liters. Common half-gallon containers: milk, orange juice, ice cream.

No. 1 US liquid gallon = 128 US fl oz = 3,785.41 mL. 1 UK imperial gallon = 160 UK fl oz = 4,546.09 mL = 153.72 US fl oz. The UK gallon is 20.09% larger than the US gallon. Always verify “gallon” means US or UK in British car specs, recipes, and product manuals.

5 US gallons = 5 x 128 = 640 US fluid ounces = 20 quarts = 40 pints = 80 cups = 18,927 mL = 18.93 liters. Standard gas can, 5-gallon water jug, and standard homebrew batch size.

55 US gallons = 55 x 128 = 7,040 US fluid ounces = 208.198 liters. A UK 55-gallon drum = 55 UK gallons = 250.035 liters = 8,454.72 US fl oz (about 20% more). Always confirm whether “55-gallon drum” means US or UK gallons when purchasing industrial quantities.

Rectangular: Length(ft) x Width(ft) x Average Depth(ft) x 7.48052 = US gallons. Round: Pi x Radius^2 x Depth x 7.48052. Average depth = (shallow end + deep end) / 2. Example: 14 x 28 ft pool, 5 ft avg depth = 14 x 28 x 5 x 7.48052 = 14,651 US gallons.

1 US quart = 32 US fluid ounces = 0.25 US gallons = 2 US pints = 946.353 mL. 4 quarts = 1 US gallon = 128 fl oz. Common quart containers: motor oil, small paint cans, deli soup.

2 US gallons = 2 x 128 = 256 US fluid ounces = 8 quarts = 16 pints = 32 cups = 7,570.824 mL = 7.571 liters.

1 US gallon of water = 128 US fluid ounces. By weight: approximately 8.34 pounds (133.5 weight ounces) at 68 degrees F. Fluid ounces measure volume, not weight. 1 fluid oz of water = about 29.57 grams (1.044 avoirdupois oz by weight).

1 US pint = 16 US fluid ounces = 0.125 US gallons = 2 US cups = 473.176 mL. 8 pints = 1 US gallon = 128 fl oz. UK pint = 20 UK fl oz = 568.261 mL (25% larger than US pint).

1 half-barrel keg = 15.5 US gallons = 1,984 US fl oz = 58.673 liters. Holds approximately 165 twelve-oz beers, 124 US pints (16 fl oz), or 82 pints (24 fl oz). The most common keg size at US bars and restaurants.

128 fl oz per gallon / 16 fl oz per bottle = 8 bottles. A gallon = 8 sixteen-oz water bottles. For 16.9 fl oz (500 mL) standard water bottles: 128 / 16.9 = 7.57 bottles per gallon (you need about 7.5 bottles to equal 1 gallon).

128 fl oz per gallon / 8 fl oz per cup = 16 cups. A gallon = 16 standard 8-oz cups. Equivalently: 1 US gallon = 16 US cups = 8 US pints = 4 US quarts.

3 US gallons = 3 x 128 = 384 US fluid ounces = 12 quarts = 24 pints = 48 cups = 11,356.235 mL = 11.356 liters.

The US dry gallon = 4 US dry quarts = 4.40488475 liters = approximately 268.8025 US fluid ounces. It is 40.6% larger than the US liquid gallon (128 fl oz). Used only for agricultural dry goods: grain, berries, produce. All consumer, commercial, and industrial liquid products in the US use the liquid gallon = 128 fl oz.

10 US gallons = 10 x 128 = 1,280 US fluid ounces = 40 quarts = 80 pints = 160 cups = 37,854.12 mL = 37.854 liters. Common 10-gallon aquarium, and some larger motorcycle fuel tanks.

A gallon jug of milk = 128 US fluid ounces, same as any liquid gallon. By weight: 1 gallon of whole milk weighs approximately 8.6 pounds (slightly more than water, due to fat and protein), which is about 137.6 avoirdupois ounces by weight, different from fluid ounces.

1.5 US gallons = 1.5 x 128 = 192 US fluid ounces = 6 quarts = 12 pints = 24 cups = 5,678.118 mL = 5.678 liters.

For UK MPG calculations: 1 UK gallon = 160 UK fl oz = 153.72 US fl oz = 4,546.09 mL. To convert UK MPG to US MPG: multiply by 0.8326 (= 3.785411784 / 4.54609). UK “50 MPG” = 50 x 0.8326 = 41.63 US MPG. This gap explains why British car fuel economy figures look better than US EPA figures for the same car.

1 US petroleum barrel = 42 US liquid gallons = 42 x 128 = 5,376 US fluid ounces = 158.987 liters = 158,987 mL. The 42-gallon US oil barrel is the standard unit for crude oil pricing and trading. It is NOT the same as a 55-gallon industrial drum. Source: EIA.gov.

1 liter = 1,000 mL / 29.5735295625 mL per fl oz = 33.814 US fluid ounces. 1 liter = 0.2642 US gallons. A 2-liter soda bottle = 67.628 US fl oz = 0.5284 US gallons. 1 US gallon = 3.785411784 liters = 128 fl oz.

Related Volume Calculators

🔁 Ounces to Gallons Reverse: 128 fl oz = 1 US gal. 640 fl oz = 5 gal. UK gallon = 153.72 US fl oz. Batch decoder. 📦 Cubic Feet to Gallons 1 cubic ft = 7.48052 US gal. Pool volume: L x W x depth = cu ft x 7.48 = gallons. Aquarium sizing. 🧪 Liters to Gallons 1 L = 0.2642 US gal. 3.785 L = 1 US gal. EU recipe liters to US gallons. Fuel tank decoder. 📏 Gallons to Liters 1 US gal = 3.785 L. 5 gal = 18.93 L. 55 gal = 208.20 L. UK gallon vs US gallon explained. 🍺 Fl Oz to mL 1 fl oz = 29.574 mL. 128 fl oz = 3,785 mL = 1 US gal. UK fl oz = 28.413 mL. TSA 3-1-1. ☕ Cups to Gallons 16 US cups = 1 US gallon. 8 cups = 1/2 gal. 4 cups = 1 quart. Recipe scaling to gallon batches. 📐 mL to Fl Oz 30 mL = 1.014 fl oz. 3,785 mL = 128 fl oz = 1 US gal. EU recipe mL to US fl oz decoder. 🟦 Pints to Gallons 8 US pints = 1 US gal. Half-barrel keg = 124 US pints. UK pint = 20 UK fl oz (25% larger).

Legal Disclaimer and Editorial Transparency

The Gallons to Ounces Converter on USCalculators.com is for educational and informational purposes only. Exact: 1 US liquid gallon = 128 US fluid ounces = 3,785.411784 mL = 3.785411784 liters = 4 US quarts = 8 US pints = 16 US cups. Source: NIST.gov NIST Handbook 44. 1 UK imperial gallon = 4.54609 liters = 160 UK fluid ounces = 1.20095 US liquid gallons = 153.722 US fluid ounces. US dry gallon = 4.40488475 liters (agriculture only, not used for consumer liquid products). Pool volume formula (rectangular: L x W x average depth x 7.48052) is approximate; actual pool volumes may vary due to pool shape irregularities, wall thickness, and equipment displacement. Pool chemical dosing references are for general informational purposes only; always follow specific product label directions, consult pool professional guidance, and test water chemistry before adding chemicals. Pool chemical safety at CDC.gov/healthywater/swimming. NSF at NSF.org. EPA chemical guidance at EPA.gov. Fuel economy data: EPA and DOE at FuelEconomy.gov. Fuel economy varies by driving conditions, vehicle condition, and load. Beer keg volumes: TTB regulations at TTB.gov. NIAAA alcohol guidelines at NIAAA.nih.gov. Industrial drum regulations: EPA at EPA.gov/rcra. DOT at Transportation.gov. This tool does not constitute professional engineering, chemistry, or automotive advice.

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