Free swimming pool calculators
Simple Tools for Healthier Pools
Calculate pool volume, chemical dosages, pump size, heating costs and more. Accurate results in seconds, with the formula and the assumptions shown every time.
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Tools. Guides. Answers. All in one place.
Popular Calculators
The tools people reach for most.
Calculators by Category
Browse the full range.
Water & Volume
Volume, surface area, filling time and more.
1 calculator
Pool Chemistry
Chlorine, pH, alkalinity, CYA, salt and more.
10 calculators
Equipment
Pumps, filters, heaters and flow rates.
6 calculators
Cost & Energy
Heating, electricity and maintenance costs.
4 calculators
Maintenance
Schedules, cleaning and water care.
2 calculators
Pool Water Health Check
Enter your test results and see what is in range, what is not, and which one to fix first.
Check My Pool WaterNot sure where to start?
Read the step-by-step guides on pool care, maintenance and water chemistry.
Browse Pool GuidesCommon Pool Problems
What went wrong, and what to do about it.
Green Pool
Causes, fixes and how to stop it coming back.
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Cloudy Pool
Why water goes hazy, and what actually clears it.
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Pool Algae
Identifying green, black and mustard algae.
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Foamy Water
What causes foam on the surface and how to fix it.
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High pH
Why pH climbs, and how to bring it back down.
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Low Chlorine
The usual reasons chlorine will not hold.
Learn moreFeatured Pool Guides
Longer reads on keeping a pool in good shape.
What Is a Lap in a Pool?
A lap means one length to a competitive swimmer and two to almost everyone else. Here is how…
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What It Costs to Heat a Swimming Pool
What heating a pool actually costs per month by gas, heat pump and solar, and the one change…
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How Much Salt to Add to a Pool
How much salt a pool needs to reach its target ppm, how many bags that works out as,…
Read moreHow It Works
Three steps, no sign-up, no guessing.
Enter your pool
Measurements or test readings — in feet and gallons, or metres and litres.
Get the answer instantly
The maths runs as you type. Nothing is sent anywhere, and nothing is stored.
See how it got there
Every calculator shows its formula, a worked example, and what it assumes.
Find the right pool calculator
Twenty-three tools for volume, chemistry, equipment and running costs.