poolcntrl

Free pool chemistry calculator

Enter your readings. Get the exact amount to add — from the same engine as the app.

Your pool

Your readings

Fill in what your kit gave you and leave the rest blank.

Your plan

Example — 20,000 gal plaster pool

Free chlorine
0.5 ppm
Stabilizer (CYA)
60 ppm
pH
7.5

Add 166.5 fl oz of Liquid Chlorine 10%

Free chlorine 0.5 ppm → 7 ppm, because 60 ppm of stabilizer raises the target.

20,000 gal × 6.5 ppm ÷ 10% → 166.5 fl oz

That is the whole calculation — your pool’s volume, how far the reading has to move, and the strength of the product. Where our numbers come from →

Put your own readings in on the left and tap “Get my plan” to replace this with yours.

That dose is real — the same deterministic engine the app runs, same answer every time.

Download on theApp Store

Questions about this calculator →