How to calculate a excavation dirt removal
Digging a hole produces more dirt than the hole itself holds, because loose soil takes up extra space.
- Measure the length, width, and depth of the excavation.
- Read the volume in place, called bank volume.
- Multiply by a swell factor of about 1.2 to 1.3 for typical soil to estimate the loose volume in the truck.
- Plan trucks and dump fees from the loose volume and weight.
Worked example
For a typical excavation dirt removal with length 30 ft, width 20 ft, depth 4 ft, the volume is 2,400.00 cubic feet. Divide by 27 for 88.89 cubic yards. With a 10 percent allowance, plan for 97.78 cubic yards.
In dirt, 88.89 cubic yards weighs about 106.67 US tons at a planning value of 2,400 pounds per cubic yard.
Excavation Dirt Removal 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 by 20 ft, 3 ft deep | 1,200.00 | 44.44 | 48.89 | 53.33 |
| 30 by 20 ft, 4 ft deep | 2,400.00 | 88.89 | 97.78 | 106.67 |
| 40 by 30 ft, 6 ft deep | 7,200.00 | 266.67 | 293.33 | 320.00 |
| 60 by 40 ft, 8 ft deep | 19,200.00 | 711.11 | 782.22 | 853.33 |
Tips
- Rock and clay swell differently from sand.
- Sloped excavation walls add volume to your count.
- Check local rules on where soil can be dumped.
Common mistakes to avoid
- Using the hole size as the truck volume.
- Ignoring sloped walls.
- Underestimating the weight of wet soil.
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 excavation dirt removal?
Multiply the dimensions in feet and divide by 27. The example above, length 30 ft, width 20 ft, depth 4 ft, needs 88.89 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 excavation dirt removal material weigh?
88.89 cubic yards of dirt weighs about 106.67 US tons as a planning value.