How Much Chlorine Should You Add to Your Pool?

Reviewed 2026-04

Use fresh free chlorine (FC) and stabilizer (CYA) tests to work out a routine addition. Match the chemical and strength on your label. CYA sets the minimum target; complete the swimming checks below before anyone gets in.

See how the calculations work in our methodology

Pool volume (gallons)

Example volumes (gallons):

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Current FC (ppm)

Target FC (ppm)

CYA level (ppm)

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Test CYA with a suitable kit or at a pool store before choosing an FC target; never guess the level. You can use the Taylor K-2006C test kit (Amazon →) for testing. If you need to add stabilizer, use the CYA dosing calculator →

Chlorine source

10% liquid pool chlorine (trade percentage)12.5% liquid pool chlorine (trade percentage)8.25% household bleach (label % by weight)6% household bleach (label % by weight)Dichlor granules (56% available chlorine)Cal-hypo (65% available chlorine)

At measured CYA 30 ppm, the routine FC minimum is 2 ppm. Your FC is 1 ppm. If it’s below that minimum, correct it before swimming. Choose a suitable FC target before you calculate an addition.

A dose calculation cannot clear a pool for swimming. Before anyone swims, test free chlorine (FC) and pH. Keep pH at 7.2–7.8, with clear water, the bottom visible and no visible algae. FC must meet both the minimum for measured CYA and the chlorine label’s re-entry range. CDC minimums are 1 ppm without stabilizer and 2 ppm with it; a pool with CYA can require more. Test FC and pH at least twice daily, and more often during heavy use.

Confirm your inputs

Before you use a dose, compare every input with your fresh tests and measured pool volume. Confirm each example value only after you’ve checked it. When you change a value, you’ll need to confirm it again.

I confirm pool volume (gallons): 15000I confirm current FC (ppm): 1I confirm measured CYA (ppm): 30

Compare liquid chlorine

Enter your measured gallons and fresh tests above to work out how much you need.

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Product option

Champion

Liquid Chlorine (1-Pack) · 1 gallon jug (12.5%)

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ProSide

Chlorinating Liquid (10%) · 2-gallon case (10%)

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Chlorine forms in water without stabilizer

Use this approximate table only for water without CYA. The percentages don’t show how much of your FC is active in stabilized water or whether it’s safe to swim. Choose your FC target from measured CYA and complete the swimming checks above.

pH	HOCl fraction (%) without CYA	Note
7.0	73%	Below the swimming pH range used here
7.2	66%	Lower end of the pH range used here
7.4	55%	Within pH range; FC still needs testing
7.6	44%	Within pH range; label re-entry limits still apply
7.8	33%	Upper end of the pH range used here
8.0	25%	Above the swimming pH range used here
9.0	3%	Above the swimming pH range used here

Keep this reference to water without CYA. Before anyone swims, use the FC, CYA and pH checks above, regardless of the percentage shown.

Frequently asked questions

How does CYA change the chlorine target?

Test CYA before choosing your free-chlorine target. The tool checks that target against a CYA-based minimum. CDC minimums are 1 ppm FC without stabilizer and 2 ppm with it; the chart can call for more. Here, routine dosing starts at a 2 ppm target even with zero CYA, and stops if current FC or the target exceeds 10 ppm.

Can I swim once I have added the calculated dose?

Keep swimmers out until fresh tests and the pool’s condition meet every check: FC at the minimum for measured CYA, pH at 7.2–7.8, clear water with the bottom visible, no visible algae and the label’s re-entry conditions. Adding the calculated dose doesn’t clear the pool for swimming. Test FC and pH at least twice daily, and more often during heavy use, as CDC guidance calls for.

Which strength on the chlorine label should I enter?

Match the formulation on your bottle or bag. Pool-liquid presets use trade-percent available chlorine; bleach presets convert weight-percent sodium hypochlorite using approximate solution density and chlorine equivalence. For dry chlorine, use available chlorine, which can differ from ingredient purity. Product suggestions must match the same strength and basis as your dose.

Should I dissolve granular chlorine before adding it?

Follow your exact product label and pool-surface instructions. Some granules need dissolving first; others must go straight into the pool. Never mix chemicals or use a contaminated container. After the required circulation and waiting time, test FC again and use that reading for any further addition.

Related calculators

How we calculate this
Your result uses the formulas explained in our methodology. Read the assumptions for your calculation before you use the result.