Cubic feet
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Concrete yardage calculator
How much concrete do you need?
Enter your dimensions and get the answer the way the pros figure it — in cubic yards — plus bag counts, ready-mix loads, weight and a waste margin built in.
Dimensions
FIG. 01Volume ÷ 27 = cubic yards. Pros order to the nearest ½ yard and add a waste margin — running short mid-pour risks a cold joint.
You need
—cu yd
Order to nearest ½ yd → — · —
Cubic meters
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80 lb bags
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60 lb bags
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Est. weight
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Best buy
see above
The concrete toolkit
How it works
Concrete volume is just length × width × thickness. The catch is the units: dimensions come in feet and inches, but concrete is sold in cubic yards (27 cubic feet) by the truck, or in 60- and 80-lb bags for small jobs. This tool converts everything, adds your waste margin, rounds the order up to the nearest half yard the way a supplier expects, and tells you whether bags or a truck is the smarter buy.
cubic yards = (length × width × thickness in feet) ÷ 27 × (1 + waste%)
FAQ
How much concrete do I need?
Measure length, width and thickness, multiply them for cubic feet, then divide by 27 for cubic yards — the unit concrete is sold and delivered in. This calculator does it instantly and also shows bag counts and ready-mix loads.
Should I buy bags or order a ready-mix truck?
Bagged concrete usually wins under about 1 cubic yard; ready-mix wins above roughly 2 yards once you factor delivery and short-load fees. Our bags-vs-ready-mix calculator finds the breakeven for your exact size.
Why think in cubic yards instead of square feet?
Because that's how concrete is priced and delivered. Square footage ignores thickness — a 4-inch and a 6-inch slab over the same area differ by 50% in concrete. Cubic yards capture the real volume you'll pay for.
How much waste should I add?
Most pros add 5–10%. Uneven subgrade, spillage and over-excavation all eat into your pour, and coming up short mid-job risks a cold joint. The calculator defaults to a 10% margin you can change.