Pond Calculators
Free calculators for pond volume, pump size, head height, waterfall flow and running cost. They run in your browser and nothing you enter is sent anywhere.
Good pump decisions start with a few numbers. These calculators work them out in your browser: nothing you type is sent to us or stored on a server. Each one gives a planning estimate, shows the assumptions behind it, and tells you what to check next.
Start here
- Pond pump size calculatorThe all-in-one tool: pond volume, target flow range and estimated head from your dimensions and pipework.
- Pond pump match quizSeven quick questions that point you to the type of pump that suits your pond.
Individual calculators
- Pond volume calculatorGallons and litres from the shape, size and depth of your pond.
- Flow rate (GPH) calculatorThe flow to aim for from your pond volume and turnover target.
- Head height calculatorVertical lift plus the losses in your pipe and fittings.
- Waterfall flow calculatorThe flow a spillway needs for the width and look you want.
- Energy cost calculatorWhat a pump costs to run per month and per year at your electricity rate.
Planning tools
- Pond layout visualizerSketch where the pump, filter, waterfall and socket will go.
- Pond maintenance trackerA checklist and log for cleaning and seasonal care, saved in your browser.
How to use the results
A calculator can tell you the flow and head your system needs. It cannot tell you what a particular pump will deliver, because that depends on the pump’s own performance curve. Take the two numbers, flow and head, to the manufacturer’s curve for any pump you are considering, and choose one that meets your flow at your head. Our guide to sizing a pond pump explains the method, and head height explained shows how to read a curve.
The calculators use standard geometry, commonly used turnover rules of thumb and the Hazen-Williams equation for pipe friction. They give estimates for planning. Filters, UV clarifiers, valves and nozzles add resistance that only their manufacturers can quantify, so always check the manuals for your own equipment.