Pond Volume Calculator
Know your pond volume before you size a pump, dose a treatment, or add fish. Pick the shape, enter the surface dimensions and average depth, and get litres and gallons.
Your results
Worked example
A rectangular pond is 3 m long, 2 m wide, and averages 0.6 m deep:
- Volume: 3 m × 2 m × 0.6 m = 3.6 m³ = 3,600 L
- US gallons: 3,600 ÷ 3.785 = 951 gal
- Imperial gallons: 3,600 ÷ 4.546 = 792 gal
The same surface in an oval shape holds about 21 percent less, roughly 2,830 L, because the ellipse formula (pi divided by 4, about 0.785) replaces the full rectangle. Picking the right shape matters more than measuring to the centimetre.
How this calculator works
Gallon figures use 3.785 litres per US gallon and 4.546 litres per imperial gallon. Pond equipment sold in Canada is usually rated in US gallons per hour, while older Canadian references may use imperial gallons, so both are shown. Average depth is the number that moves the result most: measure depth in a few spots and average them rather than using the deepest point.
Common questions
How much pump do I need for this volume?
A common rule is to circulate the full pond volume at least once every two hours for a fish pond, so divide your litres by two for the minimum pump rating in litres per hour, then check the rating at your actual lift height, not at zero head.
Why does my pond hold less than this calculator says?
Shelves, sloped sides, rocks, and a water level below the rim all reduce real volume. If treatments matter, err on the side of the lower estimate and dose for about 90 percent of the calculated volume.
Estimates only. Results are provided for planning purposes and assume regular shapes and the average depth entered. Actual volume varies with pond contours. Verify before dosing treatments or stocking fish. Mississippi Maple accepts no liability for decisions made using this calculator.