How many cubic feet are in one cubic yard?

One cubic yard contains 27 cubic feet. Divide cubic feet by 27 to convert to cubic yards.

Should I include waste?

A small allowance can help with uneven subgrade, spillage and form variation, but it should not replace careful measurement. Ask your ready-mix supplier what allowance is suitable for the pour.

Are bag yields exact?

No. Bag yield varies by product and water addition. The calculator uses common example yields; the yield printed on the selected product bag is the value to follow.

Does this calculator design the slab?

No. It estimates volume only. Slab thickness, reinforcement, base preparation and concrete strength depend on the project and local requirements.

Home project calculator

Concrete Calculator

Estimate ready-mix volume in cubic yards and compare approximate 40, 60 and 80 lb bag quantities for rectangular or circular pours.

Live estimate

Enter project measurements

Area shapeLengthftWidthftFinished depthinAllowance%

Estimated order volume

1.3 yd³

Includes the selected allowance. Ready-mix suppliers may round orders.

Measured volume: 1.23 yd³
Order volume: 35 ft³
80 lb bags: 59
60 lb bags: 78
40 lb bags: 117
Metric volume: 0.99 m³

Transparent calculation

Formula used

Volume (ft³) = area (ft²) × depth (in) ÷ 12

Cubic yards equal cubic feet divided by 27. The selected waste allowance is applied only after the geometric volume is calculated.

Worked example

A 10 × 10 ft slab at 4 inches deep is 33.33 ft³, or about 1.23 yd³ before waste. With 5% added, the order estimate is about 1.30 yd³.

How to use this estimate

1Choose a rectangular or circular pour.
2Enter finished dimensions and concrete depth.
3Add a small allowance for grade variation and handling only when appropriate.
4Confirm the order quantity or bag yield with the concrete supplier.

Concrete Calculator FAQs

Answers to the most common measurement and ordering questions.