Concrete Calculator

Estimate concrete volume, cubic yards, and bag counts for slabs, pads, footings, walkways, and other concrete projects using length, width, and thickness.

Calculate Concrete Needed

Your result will appear here.

How concrete is calculated

Volume formula:
Length × width × thickness = total volume

Conversion formula:
Cubic feet ÷ 27 = cubic yards

This calculator estimates total concrete volume, cubic yards, and approximate bag count with extra material added.

Why concrete estimates matter

Knowing how much concrete you need helps when planning slabs, pads, patios, footings, and other projects, budgeting materials, and avoiding running short during a pour.

Extra material is often useful for minor grading differences, spills, and form variations.

What your result means

Your result shows the estimated concrete volume based on the dimensions entered. The total includes an optional extra percentage to help cover waste or slight overages.

The estimate also includes an approximate bag count based on the bag size selected. For larger projects, ordering by cubic yard is often more practical than bags.

Concrete calculator tips

Frequently asked questions

How do you calculate concrete volume?

Multiply length by width by thickness to get total volume, then convert as needed to cubic feet, cubic meters, or cubic yards.

How many cubic feet are in a cubic yard?

One cubic yard equals 27 cubic feet.

Should I add extra concrete?

Yes for many projects. Extra concrete helps cover spillage, over-excavation, uneven forms, and minor variations in depth.

Can I use this for bag estimates?

Yes. This calculator provides an approximate bag count based on common 40 lb, 50 lb, 60 lb, and 80 lb concrete bag yields.