Concrete slab volume

Concrete Calculator for Slabs

Find the raw concrete volume for a rectangular slab using its length, width, and thickness. Enter feet for length and width and inches for thickness.

Slab volume

Enter your slab dimensions

Use finished slab dimensions. Results are raw volume without waste.

Enter dimensions, then calculate.

Required concrete volume—yd³

Concrete volume in cubic feet—ft³

Concrete volume in cubic meters—m³

Methodology 1.0.0 · Calculator 1.0.0

How the calculation works

Length × width × thickness gives the slab volume. Thickness entered in inches is converted to feet before calculating cubic feet. Cubic feet are divided by 27 to convert to cubic yards.

Verified example

24 ft × 24 ft × 4 in slab

7.11 yd³192.00 ft³

This fixed example comes from the calculator’s independently derived known-answer test case C.

Measurement tips

Measure the finished slab length and width at right angles.
Enter the planned uniform slab thickness in inches.
Treat the result as geometric volume, not as an order recommendation.

Concrete Slab Formula Reference

This reviewed method calculates raw geometric volume for a rectangular concrete slab. Calculator and formula provenance is stored with the definition and shown quietly beside the calculator.

Dimensional derivation

The slab is modeled as a rectangular prism. Its raw volume is:

volume = length × width × thickness

The calculator normalizes all three length inputs to meters before formula execution, so the product is cubic meters. The reviewed formula module contains only this dimensional multiplication. Unit conversions are owned by the shared units package.

The exact U.S. customary conversions used by the unit registry are:

1 inch = 0.0254 meter
1 foot = 12 inches = 0.3048 meter
1 cubic foot = 0.028316846592 cubic meter
1 cubic yard = 27 cubic feet = 0.764554857984 cubic meter

For user inputs expressed in feet and inches, the equivalent hand derivation is:

thickness_ft = thickness_in / 12
volume_ft3 = length_ft × width_ft × thickness_ft
volume_yd3 = volume_ft3 / 27

Assumptions

Length and width are perpendicular plan dimensions.
Thickness is uniform across the complete slab.
Inputs describe finished geometric dimensions.
IEEE-754 double precision is sufficient for this low-risk geometry calculation.

Included

Raw rectangular slab volume.
Exact, unrounded output in cubic meters, cubic feet, and cubic yards.
Separately rounded display values using the reviewed display policy.

Not included

Waste, spillage, over-excavation, uneven subgrade, or recommended order volume.
Pricing, bags, truckloads, labor, gravel, rebar, excavation, or regional factors.
Structural, code, engineering, or placement advice.

This version does not conflate raw calculated volume with a recommended concrete order quantity.