Concrete Volume & Order Calculator
Calculate concrete volume in cubic feet and yards with an adjustable allowance and practical order rounding.
Editorial review: 2026-09-29 · How we review technical content
Key takeaways
- Calculate rectangular concrete volume and an adjusted order quantity.
- The result assumes a rectangular uniform-thickness placement; thickened edges, slopes, trenches, blockouts, and irregular shapes should be calculated separately.
Concrete Volume & Order Calculator
Calculate rectangular concrete volume and an adjusted order quantity.
What this calculator does
Calculate rectangular concrete volume and an adjusted order quantity.
The tool converts thickness from inches to feet, multiplies length × width × thickness, converts cubic feet to cubic yards, applies the allowance, and rounds up to the selected ordering increment.
How to use the result
The result assumes a rectangular uniform-thickness placement; thickened edges, slopes, trenches, blockouts, and irregular shapes should be calculated separately.
How this calculator works
The geometric volume is length × width × thickness. Thickness is converted from inches to feet, the result is converted from cubic feet to cubic yards, and the allowance is applied before the optional order increment rounds upward.
Field thickness variation can dominate the allowance. A 4-in. slab with ruts or low subgrade is not really a uniform 4-in. prism, so spot-check grades and calculate thickened edges separately.
Input checklist
- Length: Enter the project-specific length in ft.
- Width: Enter the project-specific width in ft.
- Thickness: Enter the project-specific thickness in in.
- Allowance: Enter the project-specific allowance in %.
- Order increment: Enter the project-specific order increment in yd³.
Worked example
A 20 × 10 ft slab at 4 in. thick is about 2.47 yd³ geometrically. With 7% allowance it is about 2.64 yd³ before order rounding.
Field checklist
- Measure inside form dimensions.
- Check actual thickness from grade to top of concrete.
- Calculate thickened areas separately.
- Confirm the producer’s ordering increment.
References & further reading
- ACI SPEC-301-20 — Specifications for Concrete Construction — Reference specification used when incorporated into project specifications.
- NRMCA Concrete In Practice (CIP) — Industry education covering common concrete field problems and practices.