Construction calculator
Concrete Calculator
Estimate concrete cubic yards for slabs, patios, walkways, pads, and other rectangular concrete pours.
Concrete volume
Concrete Yards Calculator
Estimate concrete volume from length, width, and slab thickness.
Concrete needed
1.358 cu yd
Includes 10% extra. Base volume is 1.235 cu yd.
Area
100 sq ft
Length x width
Base cubic feet
33.33 cu ft
Before extra allowance
Base cubic yards
1.235 cu yd
Cubic feet / 27
Formula
cubic yards = length ft x width ft x thickness ft / 27
Convert thickness to feet first. A 4 inch slab is 0.3333 feet thick.
Common Slab Examples
| Size | Thickness | Base concrete |
|---|---|---|
| 10 ft x 10 ft | 4 in | 1.235 cu yd |
| 12 ft x 12 ft | 4 in | 1.778 cu yd |
| 20 ft x 20 ft | 4 in | 4.938 cu yd |
| 20 ft x 30 ft | 6 in | 11.111 cu yd |