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Concrete Calculator

Last Updated: 21st August 2025

A tool to calculate concrete volume and cost for your project

Building a patio? Laying a slab? Filling in your enemies’ moat? Whatever your project, this calculator will tell you how much concrete you need and how much lighter your bank balance is about to become.

How to use the concrete calculator

This calculator works out how much concrete you’ll need based on your slab or footing dimensions. It also gives you a cost estimate, whether you’re buying in bulk or mixing bags yourself.

Enter your dimensions

Measure the length, width, and depth of the area you’re concreting – all in metres. The calculator handles the volume maths. You just need a tape measure and possibly a second pair of hands.

Depth

This one catches everyone out. Convert from mm to m:

  • 100mm = 0.1m
  • 150mm = 0.15m
  • You get the idea

If your ground’s uneven or your mixing technique is ‘generous’, leave the wastage set to 10%.

Concrete costs

You’ve got two ways to cost it:

Option 1. Delivered concrete

Enter your cost per cubic metre. This suits big jobs, or if a drum of wet cement showing up on your street feels exciting.

Option 2. Bagged concrete

Enter the bag size in kg and the price per bag. This is for when you’re doing it yourself, or your wheelbarrow’s feeling underemployed.

The calculation

The calculator works out the base volume in cubic metres, adds your wastage percentage, and then:

  • Estimates the cost for delivered concrete based on m³ price
  • Estimates number of bags needed based on standard density (2400kg/m³)
  • Calculates total bag cost

It’s all mixed in for you

You’ll see total volume, bag quantities, and costs update as you change inputs. Switch between delivery and DIY mode to see what suits your project (and your patience).

No signup, no fluff, just quick concrete maths.

Quick and easy

Concrete Volume and Cost Calculator

Works out concrete volume and cost from your dimensions. Converts depth to cubic metres, adds wastage, and shows you the numbers for both bulk delivery and bagged mix. Enter length, width, depth, and your preferred cost method – the calculator does the rest.

Options

Dimensions

Enter the dimensions of your slab or footing in metres.

? For accurate results, remember to convert your depth measurement into metres (e.g., 100mm = 0.1m, 150mm = 0.15m).
? It is good practice to add extra concrete to account for uneven ground or spills. 5-10% is typical.

Concrete Details

Add the cost of your materials. Fill in either the cost per m³ or the cost per bag to get a calculation.

? Enter the price per cubic metre for delivered concrete. This is typically used for larger projects.
? Enter the weight of a single bag of concrete mix. Common sizes are 20kg or 25kg.
? Enter the price of a single bag of concrete mix. This is used to calculate the cost for smaller projects.

Enter your dimensions and concrete details above to get a calculation.

Why use our concrete calculator?

Because guessing with concrete usually means one of two things: running out halfway through a pour or paying for a truckload you didn’t need. This calculator takes away the uncertainty. Enter your dimensions and costs, and it tells you exactly how much concrete your project will eat up and how much it will cost.

It works for both delivered concrete and bagged mix, so you can compare options instantly and decide whether bulk delivery or a DIY mix makes more sense for your job. You’ll see total volume, bag counts, wastage, and costs update as you tweak the numbers, saving you the hassle of juggling tape measures, density conversions, and mental arithmetic.

The benefit is simple: no guesswork, no hidden steps, and no nasty surprises when the lorry turns up or the last bag runs out. Just quick, clear concrete maths that helps you get the job done right first time.

Our guarantees to you!

Based on the latest data

Updated regularly using trusted UK sources.

Always free to use

Open access for everyone with no sign-up or hidden costs.

Easy to use

Clear inputs, instant results, no confusion.

Your privacy is protected

We don’t collect or store any personal information.

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Use our calculators anywhere

Our calculators are fully responsive, adjusting to any screen size. Whether you’re on your phone, tablet, or laptop, you can easily access and use them wherever you are.

The layout is designed to be simple and user-friendly, ensuring you get accurate results quickly, no matter the device.

Use them anytime, wherever you want!