Disclaimer
Every result on this site is an estimate of material quantity. Read this before you order.
Material estimates, not engineering
The calculators use standard geometric formulas and the manufacturer’s published bag yields to estimate how much concrete a shape holds. They do not design the slab, footing, column or stair. Thickness, reinforcement, base preparation, mix strength and drainage depend on soil, climate, loads and local building codes, and should come from the code, a qualified contractor or an engineer.
What the estimate does not see
- Uneven or sloped ground that makes the real thickness larger than planned.
- Forms that bow or move during the pour.
- Irregular shapes that were approximated as rectangles or circles.
- Spillage, pump-line losses and concrete left in the mixer.
- Differences between brands and products in bag yield.
The default 10% waste allowance covers typical cases, but it is your judgment whether to increase it.
Prices
Cost results use only the prices you enter. The site does not publish price averages. Plants and stores set their own prices and fees.
Verify before you order
Confirm quantities with your ready-mix plant or store, check the yield printed on the bag you buy, and follow your local building code. If a result looks wrong, tell us so we can check it.