Pond Volume Calculator
Knowing your pond's volume in litres is the starting point for two important decisions: sizing a pump powerful enough to keep the water clear and healthy, and working out how many fish you can safely stock without overcrowding. Enter your pond's length, width, and average depth below, choose a shape, and we'll estimate the total volume along with a recommended pump flow rate and fish stocking guideline.
Enter your pond dimensions
Measure length, width, and average depth in metres.
Enter a length, width, and average depth above to calculate your pond volume.
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Frequently asked questions
How do I calculate an irregular-shaped pond?
Measure the longest length and widest width of the pond as if it were a rectangle, then measure the average depth across a few points. Select "Oval / irregular" above and we apply a 0.8 correction factor to the rectangular calculation, which is a widely used real-world approximation for curved or informally shaped ponds.
How often should pond water be filtered?
As a rule of thumb, your pump and filter should turn over the entire volume of the pond roughly every 2 hours to keep water clear and oxygenated, which is why we show a recommended pump flow rate based on your calculated volume.
How many fish can my pond support?
For a lightly stocked, healthy pond, a common guideline is around one average-sized fish (such as a small goldfish) per 50 litres of water. Koi and larger fish need considerably more space per fish, so treat this as a starting point rather than a hard limit.
Does pond depth matter for fish and pumps?
Yes. Deeper areas (at least 60-90cm in parts of the pond) help fish survive cold winters and hot summers, and accurate average depth is essential for getting a reliable volume figure, since even small errors in depth are magnified across the whole pond area.