Concrete Calculator

Estimate concrete volume, weight, bags and cost for slabs, columns, tubes, curbs and stairs.

Your inputs

What are you pouring?

Dimension units

Length

Width

Outer diameter (selected length units)

Inner diameter (selected length units)

Slab depth (same units)

Thickness / height units

Tread run (selected units)

Riser height (selected units)

Number of risers

Top platform depth (selected units)

Curb width (selected length units)

Gutter width (selected length units)

Curb height above gutter (selected units)

Gutter base thickness (selected units)

More options & settings

Waste allowance (%)

Number of identical pieces

Concrete density (kg/m³)

Yield per bag (m³)

Price per bag (optional)

Delivered price per m³ (optional)

Try a worked example

5 m×4 m×0.1 m with 10% waste needs 2.2 m³.

Calculated in your browser. Your inputs stay on this device.

Starting values are examples. First click or keyboard focus clears an example so you can enter yours. Reset restores the examples.

Your result

Enter your values to calculate.

Compare scenarios

Keep up to three results and their inputs during this visit. Reset clears the comparison.

Behind the answer

Rectangles: L × W × H; cylinders: πd²H/4; tubes: π(D²−d²)H/4; multiply by quantity and waste.

How to use this calculator

All dimensions use the selected length unit. The result includes cubic meters and cubic yards.

Enter what are you pouring?, dimension units, length and review the remaining options.
Select Calculate or change a value to update the result. Read the result label and units before copying.
Use Reset to restore the worked starting values.

Formula and method

Rectangles: L × W × H; cylinders: πd²H/4; tubes: π(D²−d²)H/4; multiply by quantity and waste.

Shape-based planning estimates. Density and bag yield are user inputs, not product guarantees. Verify dimensions, reinforcement, excavation and supplier specifications.

Worked example

A 5 m × 4 m × 0.1 m slab needs 2.2 m³ with 10% waste.

Questions about concrete calculator

Can I use the result to order concrete bags?

Yes. Select the shape, enter dimensions and quantity, and add a waste allowance. Enter the product’s stated yield per bag to get a rounded-up bag count. Density and price inputs provide separate weight and cost estimates; verify product specifications and site dimensions before ordering.

What assumptions should I check?

Shape-based planning estimates. Density and bag yield are user inputs, not product guarantees. Verify dimensions, reinforcement, excavation and supplier specifications.

Are my inputs saved?

Calculations run in your browser. We store only tool IDs for favorites and recent tools. A calculation link contains your inputs only when you explicitly choose to copy one.