How to Use the Concrete Calculator
- Measure the length and width of the area.
- Enter the depth or thickness you need and choose a unit for each measurement.
- Add waste or extra material when the job calls for it, then review the volume estimate.
Concrete Calculation Formula
Convert all dimensions to feet, multiply length by width by depth, then divide cubic feet by 27 to get cubic yards. One cubic foot equals approximately 0.0283 cubic meters.
Worked Example
A 10 ft by 10 ft area covered to 4 inches has a base volume of 33.33 cubic feet, or about 1.23 cubic yards, before any waste allowance.
How Much Concrete Do I Need?
Concrete is often ordered by the cubic yard, with a supplier minimum or delivery allowance. Confirm the mix, placement method, reinforcement, and product instructions; the optional waste percentage is not a substitute for those checks.
Unit Conversions
Frequently Asked Questions
What does the concrete calculator measure?
Estimate rectangular slab concrete volume with an optional waste allowance.
Which units can I use?
Enter each dimension in inches, feet, yards, centimeters, or meters. The results are shown in cubic feet, cubic yards, and cubic meters.
Should I add extra material?
Add a waste allowance when cutting, settling, spillage, or uneven ground may affect the amount you need. The calculator shows the allowance used.
How much concrete do I need?
Concrete is often ordered by the cubic yard, with a supplier minimum or delivery allowance. Confirm the mix, placement method, reinforcement, and product instructions; the optional waste percentage is not a substitute for those checks.
How much extra concrete should I order for a slab?
Many slab orders include about 5% to 10% extra for uneven subgrade, form variation, and spillage. Choose a waste allowance that reflects the job and confirm the order with the ready-mix supplier.
Can this concrete calculator estimate footings or round columns?
This calculator is for rectangular slabs, pads, patios, and walkways. Footings with changing sections or round columns require a shape-specific volume calculation.