Construction Calculators

Concrete Slab Calculator

Calculate slab area, concrete volume, ready-mix cost, approximate weight, and bag quantities.

Last updated July 23, 2026
Slab material estimator

Concrete slab dimensions

Concrete to order
Slab area
Base volume
Estimated cost

Approximate ready-mix weight and bags

Approx. wet weight
60-lb bags
80-lb bags
Results are estimates for informational purposes. Verify critical calculations and project requirements independently.

How to Estimate a Concrete Slab

Measure the slab length and width, then enter the planned thickness. The calculator converts each dimension to feet, calculates cubic feet, and converts the volume to cubic yards.

Formula

Cubic yards = Length × Width × Thickness ÷ 27

Waste Allowance

A small allowance can help account for uneven subgrade, form variations, spillage, and measurement error.

Calculation Standards

This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.

Read our calculation methodology