How to calculate a pond
Ponds are oval or free form, and the water bowl is shaped like a shallow dish, so the oval formula gives a generous estimate.
- Measure the longest and widest points of the pond.
- Use an average depth, since banks slope inward.
- Reduce your estimate a bit, since a dish holds less than a straight sided oval.
- Convert dirt volume to loose volume to plan trucks.
Worked example
For a typical pond with length 15 ft, width 10 ft, depth 3 ft, the volume is 353.43 cubic feet. Divide by 27 for 13.09 cubic yards. With a 10 percent allowance, plan for 14.40 cubic yards.
In dirt, 13.09 cubic yards weighs about 15.71 US tons at a planning value of 2,400 pounds per cubic yard.
Pond 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 |
|---|---|---|---|---|
| 10 by 8 ft, 2 ft deep | 125.66 | 4.65 | 5.12 | 5.59 |
| 15 by 10 ft, 3 ft deep | 353.43 | 13.09 | 14.40 | 15.71 |
| 30 by 20 ft, 4 ft deep | 1,884.96 | 69.81 | 76.79 | 83.78 |
| 60 by 40 ft, 6 ft deep | 11,309.73 | 418.88 | 460.77 | 502.65 |
Tips
- Plan shelves at different depths for plants and wildlife.
- Pond liners need a smooth bed of sand or fabric.
- Check local rules about water features and digging.
Common mistakes to avoid
- Using the maximum depth for the whole pond.
- Ignoring spoil pile space.
- Not planning a drain or overflow.
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 pond?
Multiply the dimensions in feet and divide by 27. The example above, length 15 ft, width 10 ft, depth 3 ft, needs 13.09 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 pond material weigh?
13.09 cubic yards of dirt weighs about 15.71 US tons as a planning value.