Pool Chemical Calculator

Test your water, type the numbers, get exact doses. Pool Chem tells you precisely how much of each chemical to add - and keeps your whole test history on your device.

EXACT DOSING
- Free chlorine: liquid chlorine (any strength), cal-hypo, dichlor, trichlor - with CYA/CH side-effect warnings
- pH: muriatic or dry acid amounts computed with real carbonate-buffer chemistry (not a rough chart)
- Alkalinity, calcium hardness, stabilizer and salt doses in oz / lb / gallons
- CSI (saturation index) so plaster doesn't etch and heaters don't scale
- FC targets that follow your stabilizer (CYA) level
- Chlorine, saltwater (SWG) and bromine pools

POOL TOOLS
- Chlorine neutralizer: how much sodium thiosulfate to lower over-chlorinated water
- Borate (borax) dosing to your target, with the matching acid to hold pH
- Turnover time, required pump flow, fill time and heater run-time

YOUR LOG, YOUR DEVICE
- Unlimited test logging - free, forever
- Partial tests welcome: log only what you measured
- Data stays on your device. No account. No cloud.
- Export everything to CSV anytime

ONE-TIME PURCHASE
The free version is a complete calculator with unlimited logging for one pool. Pool Chem Pro is a single one-time purchase that adds unlimited pools, trend charts, CSV export, custom targets and the pool tools above.

No ads. No forced videos. No account required. No subscription. No feature removals. Ever.

Always follow chemical product labels. Add, circulate, retest.

Use it as a pool chemical calculator, pool water test log, or chlorine dosing calculator - for chlorine, saltwater (SWG) and bromine pools, spas and hot tubs.

Recent changes:
Stability and reliability improvements.