Pond Calculator
A 10 by 6 foot pond, 2 feet deep on average, holds 120.00 cubic feet and 897.66 gallons. With a 2.5 foot maximum and 1 foot of overlap on each bank, the liner is 17.0000 by 13.0000 feet.
Last updated . A 10 by 6 rectangle is filled in. Average depth starts at 2 ft and maximum depth at 2.5 ft. Overlap starts at 1 ft per bank, an example. No price.
A pond volume calculator and pond gallon calculator for a rectangle, a circle, or an oval. The pond liner calculator on the same form adds twice the maximum depth and twice the overlap to each side.
A swimming pool, not a liner pond: pool volume calculator. The hole before the liner: excavation calculator.
Pond gallons and liner
Average depth is the water. Maximum depth is the liner. Overlap opens at 1 ft on each bank so the liner line can be checked. A conservation handbook adds 300 mm on each bank, which is 0.9843 ft.
Results
Gallons from the mean depth, liner from the deep point
Rectangle water is length × width × average depth. A circle is π × radius² × average depth. An oval is π × (length ÷ 2) × (width ÷ 2) × average depth. US gallons are those cubic feet multiplied by 7.48052. Liters use × 28.316846592. The maximum depth does not change the gallons.
Each liner side is the pond side plus 2 × maximum depth plus 2 × overlap. Overlap is the allowance on one bank, so it is added twice. The box starts at 1 ft so the opening liner can be checked. A published flexible-liner note, “Flexible linings” at conservationhandbooks.com, allows 300 mm on each bank. Set the overlap unit to mm and type 300 to use that allowance. The 1 ft start is not a required hem.
Gallons and liner sides
| Pond | Gallons | Liner length | Liner width |
|---|---|---|---|
| 10 × 6 ft, average 2 ft, max 2.5 ft, overlap 1 ft | 897.66 gal | 17.0000 ft | 13.0000 ft |
| Same pond, overlap 300 mm | 897.66 gal | 16.9685 ft | 12.9685 ft |
| Round, diameter 8 ft, same depths and 1 ft overlap | 752.02 gal | 15.0000 ft | 15.0000 ft |
| Oval 12 × 8 ft, same depths and 1 ft overlap | 1,128.04 gal | 19.0000 ft | 15.0000 ft |
Worked example
Leave the 10 by 6 rectangle, average depth 2 ft, maximum depth 2.5 ft, and overlap 1 ft. Gallons reads 897.66 gal. Liner length reads 17.0000 ft · 5.1816 m. Liner width reads 13.0000 ft · 3.9624 m. 120 × 7.48052 = 897.6624, which prints as 897.66.
Pond questions
How many gallons are in the opening rectangle?
Leave Shape on Rectangle, length 10 ft, width 6 ft, average depth 2 ft, maximum depth 2.5 ft, and overlap 1 ft. Water reads 120.00 ft³ · 3.3980 m³. Gallons reads 897.66 gal. Liters reads 3,398.02 L. Liner length reads 17.0000 ft · 5.1816 m. Liner width reads 13.0000 ft · 3.9624 m.
How is the liner 17 by 13?
Each liner side is the pond side plus twice the maximum depth plus twice the overlap. Length is 10 + 2 × 2.5 + 2 × 1 = 17. Width is 6 + 5 + 2 = 13. Gallons ignore the maximum depth and the overlap. They are the plan times the average depth, 10 × 6 × 2 = 120 cubic feet, times 7.48052.
What liner does a 300 mm overlap give?
Set the overlap unit to mm and the overlap to 300, and leave the 10 by 6 rectangle, the 2 ft average, and the 2.5 ft maximum. Liner length reads 16.9685 ft · 5.1720 m. Liner width reads 12.9685 ft · 3.9528 m. Gallons stays 897.66 gal. Three hundred millimeters is 0.9843 ft. Flexible linings, on conservationhandbooks.com, sizes a liner with 300 mm past the rim on each bank. The 1 ft in the box is only an example so the liner line can be checked.
How many gallons in an 8 ft round pond?
Choose Round and set the diameter to 8 ft. The box still holds the 10 ft length until you change it. Leave average depth at 2 ft, maximum depth at 2.5 ft, and overlap at 1 ft. Water reads 100.53 ft³ · 2.8467 m³. Gallons reads 752.02 gal. Liters reads 2,846.72 L. Liner length and liner width both read 15.0000 ft · 4.5720 m. The water is π × 16 × 2. Each liner side is 8 + 2 × 2.5 + 2 × 1.
How many gallons in a 12 by 8 oval?
Set Shape to Oval, length 12 ft, width 8 ft, and leave average depth 2 ft, maximum depth 2.5 ft, and overlap 1 ft. Water reads 150.80 ft³ · 4.2701 m³. Gallons reads 1,128.04 gal. Liters reads 4,270.08 L. Liner length reads 19.0000 ft · 5.7912 m. Liner width reads 15.0000 ft · 4.5720 m. The water is π × 6 × 4 × 2.
Why are average depth and maximum depth both on the form?
Average depth is only the water. A pond is rarely a flat box, so gallons use the mean depth you judge. The liner has to reach the deepest point and climb both banks, so the sheet uses the maximum. If the average is deeper than the maximum, the note reads: Average depth is deeper than the maximum depth.
What if a side or a depth is blank?
Clear the length on a rectangle. The note reads: Enter the pond length and the pond width, each greater than zero. For a round pond the note reads: Enter a pond diameter greater than zero. A blank depth reads: Enter an average depth and a maximum depth, each greater than zero. A negative overlap reads: Overlap cannot be negative.