Example: Length: 20 ft · Width: 10 ft · Thickness: 4 in · Waste factor: 10% → Concrete needed: 2.72 cu yd.
80 lb bags (0.022 yd³ each): 124 bags
60 lb bags: 160 bags
Frequently asked questions
How do I calculate concrete? Enter your numbers above and the result updates instantly. For example: Length: 20 ft · Width: 10 ft · Thickness: 4 in · Waste factor: 10% → Concrete needed: 2.72 cu yd.
Is this Concrete Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for concrete. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.