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Concrete Calculator
Enter your dimensions to get the concrete in cubic yards, the bag count if you're mixing it yourself, and a delivered price range for both ways of buying it.
- Volume in cubic yards
- Bags at 40, 60, or 80 lb
- Ready-mix price range
Project measurements
What are you pouring? Pick a shape
Patios, sidewalks, driveways, shed pads, footings.
Measurements Tape measure or decimals
Waste allowance How much to add on top
How this number is built
The math is short, and every input is listed below so you can check it before you order.
Cement is not concrete
Cement is the gray powder that binds; concrete is that powder with sand, gravel, and water added. Many people search for a "cement calculator" and mean this: a bag of concrete mix already contains its cement, so nothing is added separately. Buying cement and aggregate to batch your own is a different job, with different ratios and its own strength table.
A yard is 27 cubic feet
Concrete is sold by volume, and one cubic yard is 3 × 3 × 3 ft, or 27 ft³. Sizing a yard as 9 ft² means ordering a third of the concrete you need.
Bag yields are the manufacturers' own
Quikrete and Sakrete agree exactly at 40, 60, and 80 lb: an 80 lb bag yields 0.60 ft³, so a yard takes 45 of them. Both publish those numbers as approximate.
Waste goes on top, then bags round up
Sakrete's own estimating guide says to add 10% to every bagged estimate. Bag counts round up to the next whole bag, the way Quikrete's calculator does it.
Ready-mix rounds to the plant's increment
Plants deliver in fixed increments, usually a half yard, but that varies. Order to your supplier's increment, and never below the calculated volume.
How far one cubic yard goes
| Thickness | Coverage per cu yd | Typical use |
|---|---|---|
| 4 in | 81 sq ft | Patio, sidewalk, shed pad |
| 5 in | 65 sq ft | Driveway |
| 6 in | 54 sq ft | Driveway, garage floor |
| 8 in | 41 sq ft | Heavy vehicle apron |
Coverage is 27 ft³ ÷ thickness, so it is exact for any thickness you enter. The typical-use column reflects common trade practice; confirm the slab thickness your job needs against ACI 332 or your local code before you order.
Setting fence posts? The fence calculator works out post spacing and the concrete that goes with it, so the two don't get counted twice.
Where these numbers come from
- Quikrete Concrete Mix (No. 1101) data sheet and Sakrete High-Strength Concrete Mix data sheet, and the two agree exactly at 40, 60, and 80 lb.
- Home Depot listed price for an 80 lb bag, August 2026, via a secondary price tracker.
- NRMCA Performance Benchmarking Survey (2023 data) average total selling price, trended to 2026 with BLS PPI series WPU1333 (+8.4% from 2023 to 2026 so far).
- Sakrete estimating guidance for bagged mix, and the Concrete Society's 5% formed to 15% unformed range for ready-mix.
- Unit weight of concrete: 140 lb/ft³, published by both Quikrete and Sakrete.
The other nine calculators
Every material, same layout, its own crew.
