How Much Concrete Do I Need?
Simple formulas, quick reference tables, and a free calculator to work out exactly how much ready-mix concrete your project requires.
Step 1
The Basic Formula
Working out how much concrete you need comes down to one simple calculation. Measure your area in metres, plug the numbers in, and you have your volume.
Then add 10% for wastage to get your order volume.
Worked Example
You want to pour a driveway that is 6m long, 3m wide, and 150mm (0.15m) deep.
Add 10% wastage: 2.7 + 0.27 = 2.97 m³
You would order approximately 3.0 m³ of ready-mix concrete.
Quick Reference
Quick Reference Tables
Don't want to do the maths? Here are the volumes for the most common domestic concrete projects. All figures assume a level sub-base and include a small rounding allowance.
Shed Bases
100mm (4") depth
| Size | Volume |
|---|---|
| 6 × 4 ft | 0.25 m³ |
| 8 × 6 ft | 0.5 m³ |
| 10 × 8 ft | 0.8 m³ |
| 12 × 10 ft | 1.2 m³ |
Driveways
150mm (6") depth
| Type | Volume |
|---|---|
| Single car (3 × 6m) | 2.7 m³ |
| Double (6 × 6m) | 5.4 m³ |
Garage Floors
150mm (6") depth
| Type | Volume |
|---|---|
| Single (3 × 6m) | 2.7 m³ |
| Double (6 × 6m) | 5.4 m³ |
Foundations
600mm wide × 200mm deep
| Length | Volume |
|---|---|
| Per linear metre | 0.12 m³ |
| 10 linear metres | 1.2 m³ |
| 20 linear metres | 2.4 m³ |
| 30 linear metres | 3.6 m³ |
Depth Guide
Common Depths Guide
Choosing the right depth is just as important as getting the area right. Here is a quick guide to the recommended concrete depth for common applications.
Paths & Light Use
Garden paths, stepping stone bases, and light pedestrian areas where no vehicle traffic is expected.
Shed Bases
Standard shed bases, greenhouse floors, and light-duty slabs for garden buildings.
Driveways & Garage Floors
Domestic driveways, garage floors, and any area that needs to support the weight of vehicles.
Foundations
Strip foundations, trench fill, and structural bases. Always check with building control for your specific project.
Pro Tips
Tips for Accurate Ordering
Getting your volume right saves time, money, and stress on pour day. Follow these five tips to make sure you order the right amount.
Always Add 10% for Wastage
No site is perfectly level and no formwork is perfectly sealed. Adding 10% to your calculated volume covers spillage, slight depth variations, and minor measurement errors. Running short mid-pour is far more expensive than a small surplus.
Measure in Metres
The formula works in metres, so convert everything before you start. Remember that 150mm = 0.15m and 100mm = 0.1m. A common mistake is entering depth in millimetres, which gives a wildly wrong result.
Account for Irregular Shapes
If your area is not a simple rectangle, break it into smaller sections (rectangles, triangles, or circles), calculate each one separately, and add the totals together.
Consider Site Access
If the truck cannot get close to your pour area, you may need a concrete pump. Pumping can add a small amount to your volume needs due to priming the line. Mention access constraints when you order.
When in Doubt, Call Us
If you are unsure about quantities, depths, or mix types, give us a call on 024 7636 1448. We help customers work out their requirements every day and are happy to advise.
Use Our Free Calculator
Don't fancy the maths? Our online concrete calculator does it all for you. Enter your dimensions, pick your shape, and get an instant volume estimate with wastage built in.
Open the Calculator
