45 Free Precision Tools

Free Concrete Calculator Hub
Slabs, Posts, Walls & Asphalt in Cubic Yards

Every concrete and masonry calculator built for US contractors and DIYers. Cubic yards, bag counts, square feet — all in American units. No metric. No sign-up. No cost.

Concrete Slab Driveway Fence Posts Retaining Wall Cinder Block Sonotube

45+

Concrete Calculators

Clusters: Flatwork, Posts, Masonry

Always Free

ACI 318 StandardsUS concrete mix ratios built in

Cubic Yards & BagsBoth outputs on every calculator

10% Waste IncludedNever run short on a job

PDF ExportShare estimates with contractors

Updated 2026Current US material prices

Flatwork & Pads Posts, Footings & Columns Masonry, Block & Asphalt

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Flatwork & Pad Calculators

Slabs, driveways, patios, floors, and specialty pads — output in cubic yards and 60/80 lb bag counts

20 Tools

Which Concrete Calculator Do You Need?

Your Project	Start With This Tool	Also Check
Pouring a concrete floor or slab	Concrete Slab Calculator	Garage Floor, Basement Floor
Building a driveway	Driveway Calculator	Asphalt Driveway (if paving)
Setting fence or deck posts	Fence Post Calculator	Deck Footing, Sonotube
Retaining wall or block wall	Retaining Wall Calculator	Cinder Block, Mortar
Brick or stone work	Brick Wall Calculator	Mortar Calculator, Brick Veneer
Concrete steps or stairs	Concrete Steps Calculator	Slab Calculator (landing)
Equipment or utility pads	AC Unit Pad or Generator Pad	Hot Tub Pad, Transformer Pad
Pool deck or surround	Pool Deck Calculator	Pool Plaster Calculator

45+

Concrete Calculators

Clusters: Flatwork, Posts, Masonry

ACI

318 Standards Referenced

Always Free

Why These Calculators

Built to Outperform Every Other Concrete Calculator Online

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Cubic Yards AND Bag Count — Both on Every Tool

Whether you are ordering a ready-mix truck or buying Quikrete bags at Home Depot, every calculator outputs both. You get cubic yards for the truck order and exact 60 lb and 80 lb bag counts for the hardware store run.

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10% Waste Factor Built Into Every Result

Every concrete calculator on this site adds a standard 10% overage to the raw calculated volume. Real pours always lose material to spillage, uneven sub-base, and form irregularities. Our outputs protect you from running short on the job.

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ACI 318 and Standard US Mix Ratios

Our bag count calculations use current ACI standard concrete mix yields: 0.45 cubic feet per 60 lb bag and 0.60 cubic feet per 80 lb bag. These are the published numbers on every Quikrete, Sakrete, and FastSet bag in the US.

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Specialty Pads Other Sites Ignore

Our hub covers pads for AC condensers, standby generators, propane tanks, commercial dumpsters, and utility transformers. These specialty pads each have specific thickness requirements that our calculators bake in automatically.

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PDF Export for Contractor Quotes

Every major concrete calculator includes a one-click PDF download. Take your cubic yard estimates and material lists directly to your concrete supplier, ready-mix company, or masonry contractor for accurate quotes.

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WhatsApp Share for Crew Coordination

Running numbers on a job site? Hit the WhatsApp share button and send the material estimate directly to your crew or supplier contact. No typing, no transcription errors, no wasted trips to the store.

Common Questions

Concrete Calculator FAQs

How many bags of concrete do I need for a 10×10 slab?+

A 10×10 foot slab at a standard 4 inch depth contains 12.35 cubic feet or 0.46 cubic yards of concrete. That requires approximately 28 bags of 60 lb concrete or 21 bags of 80 lb concrete, before the standard 10% waste factor. With waste, order 31 bags at 60 lb or 23 bags at 80 lb. Use our Concrete Slab Calculator to get an instant count for any dimensions.

How deep should a concrete driveway be?+

The standard residential concrete driveway depth is 4 inches for passenger cars and light SUVs. If you park heavy pickup trucks, RVs, or delivery vehicles, increase to 5 or 6 inches and add a rebar grid. The ACI recommends a minimum 4 inch depth over a well-compacted 4 to 6 inch gravel base for residential applications. Our Driveway Calculator lets you toggle between 4, 5, and 6 inch depths to compare material volumes.

How many bags of concrete do I need per fence post?+

A standard 8 inch diameter hole at 24 inches deep holds approximately 0.07 cubic feet of concrete, which is less than one 50 lb bag. However, for a solid, frost-resistant footing, most contractors use a 10 inch diameter hole at 36 to 48 inches deep — which holds about 0.15 to 0.25 cubic feet or roughly half of a 60 lb bag per post. Our Fence Post Calculator handles any combination of hole diameter, depth, and post count, and outputs the exact number of bags to purchase.

What is the difference between a cubic yard and a cubic foot of concrete?+

One cubic yard equals 27 cubic feet. Ready-mix concrete companies sell by the cubic yard, while bagged concrete products list coverage in cubic feet per bag. To convert: take your square footage, multiply by your depth in feet (so 4 inches = 0.333 feet), and you get cubic feet. Divide by 27 for cubic yards. Our calculators do all of this math automatically and output both units so you can order correctly whether you are buying bags or calling a ready-mix truck.

How do I calculate concrete for a circular area?+

For a circular slab like a sonotube footing or round patio, the formula is: Area = pi x radius squared (3.14159 x r x r). Multiply the area in square feet by the depth in feet to get cubic feet, then divide by 27 for cubic yards. Our Sonotube Calculator handles this automatically for any tube diameter and depth. For odd shapes, break them into rectangles and circles and add the results together.

How many cinder blocks do I need for a 8×8 foot wall?+

A standard 8×8 foot wall (64 square feet) using 8x8x16 inch CMU blocks requires approximately 112 blocks, calculated at 1.125 blocks per square foot (because the actual modular size including mortar joints is 8×8 inches). Add 5% for cuts and breakage, bringing your order to about 118 blocks. Our Cinder Block Calculator computes this instantly for any wall height and length, and also calculates the mortar bags needed to lay them.

Can I mix my own concrete or should I order ready-mix?+

For jobs under about 0.5 cubic yards (roughly a 5×5 foot slab at 4 inches deep), bagged concrete from a home improvement store is practical and cost-effective. Above half a yard, ready-mix typically becomes cheaper per cubic foot and saves significant labor. The crossover point is usually around $150 to $200 in bag costs versus a minimum ready-mix truck charge of $175 to $250 plus delivery. Our calculators give you both bag counts and cubic yards so you can compare costs for your specific project.

How thick should a retaining wall footing be?+

A standard rule of thumb for concrete retaining wall footings is that the footing should be as thick as the wall is wide and twice as wide as the wall. For a 12 inch thick wall retaining 3 to 4 feet of soil, you would need a 12 inch thick by 24 inch wide footing below the frost line. For taller walls or heavy soil loads, a structural engineer should size the footing. Our Retaining Wall Calculator uses these standard proportions for walls under 4 feet in height.

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Disclaimer & Editorial Transparency: These calculators provide material quantity estimates for planning purposes. Actual concrete volumes required depend on sub-base conditions, form accuracy, site slope, and mix consistency that this tool cannot account for. All bag count calculations use published ACI-standard yields (0.45 cu ft per 60 lb bag, 0.60 cu ft per 80 lb bag). A standard 10% waste factor is added to all results. For structural applications including retaining walls over 4 feet, load-bearing footings, and commercial pads, consult a licensed structural engineer. Always verify local building code requirements and permit obligations before pouring. External links reference ACI.org standards.

Start With the Right Concrete Calculator

45 free tools for every concrete and masonry project. Cubic yards, bag counts, and cost estimates in seconds. No sign-up required.

Concrete Slab Calculator Fence Post Calculator

Free Concrete Calculator HubSlabs, Posts, Walls & Asphalt in Cubic Yards