Concrete Volume Calculator (Cubic Yards and Bags)

Length × width × depth, plus waste. Depth is a thickness (inches or millimetres). Bags use 0.45 ft³ per 60 lb bag and 0.60 ft³ per 80 lb bag.

Inputs

Units

Results

Volume: 36.667ft³
Volume: 1.358yd³
60 lb bags: 82
80 lb bags: 62

Recommended gear

Heavy-duty wheelbarrow
Move mixed concrete to the form.
Typical range: $80–$180
Cement mixer
Worth it once the bag count leaves a mixing tub behind.
Typical range: $200–$600

Calculation method

A 10×10 ft slab 4 in thick is 33.3 ft³ (1.23 yd³) before waste. Ten percent waste is common for small pours. Metric mode shows m³; bag counts still follow US 60/80 lb yields as a planning number.

Exact formula

cu ft = L × W × (depth_in / 12) × (1 + waste/100). cu yd = cu ft / 27. Metric volume is the same pour in m³.

Ready-mix vs bags

Over about 1 yd³ (0.76 m³), ready-mix is usually cheaper than bags. Use the yardage output to quote a truck.

Frequently asked questions

How many 80 lb bags in a cubic yard?

About 45, because 27 / 0.60 ≈ 45. This tool ceils after waste.

Can I enter a footing as a long narrow slab?

Yes. Use length × width × thickness of the trench.

Why two volume outputs?

Yards talk in cubic yards; EU yards talk in m³. Both describe the same pour.

Disclaimer — no professional advice, no liability

Bag yield varies by mix and compaction. Footings, rebar displacement and slope change the order. Confirm with the bag label.

These calculators, pages and any related content are provided “as is” and “as available”, solely for general educational and informational purposes. They are simplified mathematical estimates, not a construction drawing, cut list or material takeoff, and they do not constitute engineering, architectural, structural, building-code or other professional advice.

Results can be wrong, incomplete or inapplicable to your lumber, moisture content, species, fasteners, climate, codes or use case. You must independently verify every figure, assume all risk, and have a licensed contractor, carpenter or structural engineer review any purchase or installation before you act on it.

To the fullest extent permitted by applicable law, the site operator, authors, contributors and affiliates disclaim all warranties, express or implied, and accept no liability for any direct, indirect, incidental, special, consequential or punitive damages, or for property damage, collapse, injury, death, business interruption or financial loss, arising out of or related to the use of, or reliance on, these tools or their outputs.

Some jurisdictions do not allow certain warranty exclusions or liability limitations, including for personal injury. In those places, our responsibility is limited to the maximum extent permitted by law. If you do not agree, do not use this site.