HOW IT WORKS
The calculation
Length × width × thickness in feet gives cubic feet; divide by 27 to convert to cubic yards. Apply waste to the volume.
Concrete & Masonry
Concrete Calculator
Estimate the volume of concrete for a rectangular slab. The result is a planning estimate, not a structural design or placement specification.
Keep in mind
This estimates volume only. It does not replace structural engineering, local codes, reinforcement design, or placement requirements.
COMMON QUESTIONS
About concrete estimates
How much concrete should I order?
Use the adjusted volume as a starting estimate, then confirm the order quantity with your concrete supplier and account for site conditions.
Does this calculator size a foundation?
No. It estimates volume only and does not replace structural engineering, code requirements, reinforcement design, or local construction guidance.
Want to understand the assumptions? Read the concrete estimating guide →