Concrete Volume Calculator

The Concrete Volume Calculator computes concrete volume from the relation cubic yards = length x width x (thickness / 12) / 27. It takes 3 inputs (slab length in ft, slab width in ft, slab thickness in in) and returns the concrete volume. Because this is a pure mathematical or physical formula rather than a jurisdiction-specific rule, the result never changes over time: the same inputs always produce the same answer, so you can rely on it whether you are checking homework, sizing a design, or sanity-checking another tool. Enter your values in the fields below and the result updates instantly; you can also share a permalink that pre-fills the exact calculation, which is useful for teaching, reports, or collaboration. For example, with slab length = 20 ft, slab width = 12 ft, slab thickness = 6 in, the concrete volume works out to 4.444444, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by CalculatorHub methodology, and the figure above each result carries the date it was last verified. This tool is general information and is not a substitute for professional engineering, medical, financial, or scientific advice; always check critical results against the primary source and your own judgement.

With Slab length = 20 ft, Slab width = 12 ft, Slab thickness = 6 in, the result is 4.444444.

Formula: cubic yards = length x width x (thickness / 12) / 27. Source: CalculatorHub methodology, as at 2026-06-23.

Concrete Volume4.444444

Applies to: any numeric inputs. Method source: CalculatorHub methodology, checked 2026-06-23.

The formula

cubic yards = length x width x (thickness / 12) / 27

Worked example

With Slab length = 20 ft, Slab width = 12 ft, Slab thickness = 6 in:

  1. Cubic feet = L x W x (thickness / 12) = 120.000
  2. Cubic yards = cubic feet / 27 = 4.4444
  3. Concrete Volume = 4.444444

This worked example is one of the automated golden-value tests this calculator must pass before it can publish.

What this assumes

  • Inputs are real numbers in the units shown.
  • The result is the exact value of cubic yards = length x width x (thickness / 12) / 27; general information, not professional advice.

Frequently asked questions

What formula does this use?

cubic yards = length x width x (thickness / 12) / 27, the standard form documented by CalculatorHub methodology.

Does the result ever change over time?

No. This is a pure formula with no external rate, so the same inputs always give the same result.

Official sources and verification

Reviewed by the CalculatorHub team, edited by James Graham, 2026-06-23. See our methodology. General information, not professional advice.