Pool water calculators that show their work
Every number on this site traces back to a published source. No account, no email — just the calculation.
| Tool | What it answers | Status |
|---|---|---|
| Pool volume calculator | How many gallons or litres your pool holds. Rectangular, round, oval and freeform. | Live |
| Pool salt calculator | How much salt to reach your target ppm, with staged dosing and bag counts. | Live |
| CYA / stabiliser calculator | How much cyanuric acid to add — and why you cannot filter it back out. | Live |
| Pump runtime calculator | Turnover time from your volume and flow rate. | Live |
| pH calculator | How much acid or soda ash. Requires a published dose constant before it ships. | Pending credentialed review |
| Alkalinity calculator | Baking soda and acid doses. | Pending credentialed review |
| Chlorine / shock calculator | FC targets from your CYA level, and the two standards that disagree about it. | Pending credentialed review |
Want more than a calculator?
Saved readings, dose reminders, multiple pools and CSV/PDF export are on the roadmap for a paid tier. The calculators stay free either way.
Guides
- Cloudy pool water — what to check, in order
- How long to run a pool pump
- How to winterize an above ground pool
- Closing a pool for winter
- How to backwash a pool filter
- Pool maintenance schedule
- Why is my pool cloudy?
- Black algae in pool
- Mustard algae in pool
- Cyanuric acid in a pool
- Pool pump timer: how long to run
- Pool filter fix: troubleshooting
Why you can check us
Pool dosing advice is safety-relevant, so we publish our constants and their provenance instead of asking you to trust us. The register currently holds 1 constants we consider provable, 6 industry formulas presented with their source, and 2 that are openly flagged as awaiting review by a credentialed pool professional — we would rather show that than hide it.
See the formula and source register →
Safety first: never mix chlorine products with acid. Always add chemicals to water, not water to chemicals. Follow the product label.