About Concrete Calculator
Free concrete calculators for people in the United States who need to know how much to order before they pour.
What the site does
Every calculator here answers the same question: how much concrete do I need, and what is the best way to buy it? You enter measurements, and the result gives the exact volume, the amount to order with waste, bag counts for every common bag size, cost at your own prices, and a recommendation between bagged mix and a ready-mix truck.
Who it is for
Homeowners and DIYers pouring a patio, shed base, fence posts or steps. Contractors and finishers checking an order. Estimators and builders pricing a bid. The calculators work on a phone at the job site and need no sign-up.
How the results are calculated and checked
- Each calculator uses the standard geometric formula for its shape, shown on the page with your numbers substituted so you can check it.
- Bag yields come from the manufacturer’s published data sheet, with the source and the date we checked it listed on the page.
- The calculation code has automated tests with hand-worked examples. Every formula on the site is tested against a figure worked out by hand before it is published.
- Results are material estimates. They are not structural engineering advice, and they do not replace your local building code or a contractor’s judgment on site.
How the site is funded
The site is free to use and is supported by advertising. Ads are placed below calculator results and between content sections, never over the inputs or the result. We do not sell concrete, take referral fees from suppliers, or collect your measurements.
Corrections
If you find a mistake in a formula, a yield figure or an explanation, please contact us. We check reported errors against the source and fix them.