How to calculate a concrete wall
For a wall, the width is the thickness and the depth is the height, so check which box is which.
- Measure the length of the wall.
- Enter the thickness in the width box and the height in the depth box.
- Add the footing as a separate calculation.
- Add 5 to 10 percent for waste and form bulge.
Worked example
For a typical concrete wall with length 20 ft, width 8 in, depth 4 ft, the volume is 53.33 cubic feet. Divide by 27 for 1.98 cubic yards. With a 10 percent allowance, plan for 2.17 cubic yards.
In concrete, 1.98 cubic yards weighs about 4.00 US tons at a planning value of 4,050 pounds per cubic yard.
Concrete Wall sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra | US tons |
|---|---|---|---|---|
| 20 ft long, 6 in thick, 3 ft high | 30.00 | 1.11 | 1.22 | 2.25 |
| 20 ft long, 8 in thick, 4 ft high | 53.33 | 1.98 | 2.17 | 4.00 |
| 40 ft long, 8 in thick, 8 ft high | 213.33 | 7.90 | 8.69 | 16.00 |
| 100 ft long, 10 in thick, 8 ft high | 666.67 | 24.69 | 27.16 | 50.00 |
Tips
- Walls over a few feet high need a structural design.
- Form pressure is high, so forms must be strong.
- Pour in lifts to avoid blowouts.
Common mistakes to avoid
- Mixing up thickness and height.
- Leaving out the footing.
- Not allowing for openings and corners in the count.
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How many cubic yards do I need for a concrete wall?
Multiply the dimensions in feet and divide by 27. The example above, length 20 ft, width 8 in, depth 4 ft, needs 1.98 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
How much does concrete wall material weigh?
1.98 cubic yards of concrete weighs about 4.00 US tons as a planning value.