Concrete Calculator UK
Planning a shed base or garden footings? Quickly calculate your required cubic metres and standard 25kg bags.
Calculate Concrete for Shed Bases and Footings
Welcome to ConcreteCalculator.website. Whether you are laying down a new concrete base for a garden shed or pouring foundation footings for a home extension, getting your concrete volume right is crucial in the UK. Order too little from the ready mix supplier, and you are hit with short load fees. Buy too many bags from the builders merchant, and you are wasting your money.
Using our UK concrete calculator is simple:
- Select what you are building: a concrete base, post holes or columns, or stairs.
- Enter your measurements. The tool is set to metric, so use metres for length and width, and centimetres for the depth or thickness.
- Hit calculate to get your exact cubic metres and see how many standard 25kg bags you need.
How Do You Calculate Cubic Metres of Concrete?
If you want to do the maths yourself without the calculator, calculating concrete volume in cubic metres is quite straightforward. You just need to ensure all your measurements are in metres before multiplying.
The Formula: Length in metres multiplied by Width in metres multiplied by Depth in metres equals Total Cubic Metres.
Example for a UK driveway: Let us assume you are pouring a driveway section that is 5 metres long, 3 metres wide, and 100 millimetres thick. First, convert your thickness to metres by dividing by 1000, which gives you 0.1 metres. Now multiply: 5 times 3 times 0.1 equals 1.5 cubic metres of concrete.
25kg Concrete Bag Calculator and Yields
If you are doing a small job, you will likely pick up premixed bags of concrete from places like Wickes or B and Q. In the UK, the most common bag size is 25kg. Here is what you can expect a single bag to yield once mixed with water:
| UK Bag Size | Approximate Yield in Cubic Metres | Bags needed per cubic metre |
|---|---|---|
| Standard 25kg Bag | 0.011 cubic metres | approx 90 bags |
| Standard 20kg Bag | 0.009 cubic metres | approx 110 bags |
Frequently Asked Questions
How do I calculate cubic metres of concrete?
To calculate cubic metres, simply multiply the length in metres by the width in metres and the depth in metres. For example, a 4 metre by 3 metre shed base that is 100 millimetres thick requires 1.2 cubic metres of concrete.
How many 25kg bags of concrete do I need for a cubic metre?
You will need approximately 90 standard 25kg bags of premixed concrete to make up one full cubic metre. For anything over half a cubic metre, it is usually cheaper and much easier on your back to order a ready mix delivery rather than mixing bags.
How to calculate concrete for footings?
For foundation footings, measure the total trench length in metres, multiply by the trench width in metres, and then multiply by the depth of the concrete you plan to pour in metres. This will give you the total volume required.
What is the cost of ready mix concrete in the UK?
While prices vary by region and supplier across the UK, you can generally expect to pay between 100 pounds and 150 pounds per cubic metre for standard ready mix concrete delivery.