Pool Liquid Bleach Calculator
Dose plain bleach like a chemist: pool gallons, the chlorine gap, and the % on the bottle in — gallons, ounces and cups out.
The short answer
Formula. One gallon of 10% bleach per 10,000 gallons of pool water raises free chlorine about 9.5 ppm — scale the dose to your target rise and pool volume.
Example. Raising a 15,000-gallon pool by 4 ppm with 10% bleach takes 0.63 gallon — about 81 fluid ounces.
How this calculator works
Free chlorine is measured in ppm — milligrams per liter of pool water. To raise FC you add sodium hypochlorite, and what a bottle delivers depends on its strength: a gallon of 10% liquid chlorine holds about 0.79 lb of available chlorine, while 8.25% household bleach holds about 0.65 lb. Spreading that across the pool's mass of water gives the rise: one gallon of 10% in 10,000 gallons (roughly 83,450 lb of water) lifts FC by about 9.5 ppm; the same gallon of 8.25% lifts it about 7.9 ppm.
The calculator runs that proportion in reverse. It takes your pool gallons, the gap between your current and target FC, and the percentage on the bottle — treating a jug of bleach as weighing what water does (real bleach is a few percent denser; that and the 95% chlorine-equivalence of hypochlorite are why field results can land a hair under the printed dose). Divide the gap by the rise-per-gallon of your strength and you get gallons; the readout converts to fluid ounces, cups and liters because nobody pours pool chemicals by the gallon into a small pool.
Context the raw arithmetic cannot supply: your stabilizer (cyanuric acid, CYA) level sets a sane target — the TroubleFreePool convention is roughly 7.5% of your CYA as a minimum FC (at CYA 40, keep FC above about 3 ppm and dose to whatever shock level your chart calls for when fighting algae). Bleach loses strength in storage, especially hot garages, so old jugs act weaker than their label. Dose in the evening with the pump running, pour slowly in front of a return, and never — never — mix bleach with acid, with trichlor pucks, or with anything else: chlorine gas and violent reactions are the classic pool-owner ER visit.
Sources & review date
- Dosing follows the plain-bleach method used across the pool-service industry (the same arithmetic as TroubleFreePool's dosing guides).
- Chlorine strengths: plain household bleach 5–8.25%, pool-store liquid chlorine 10–12.5% — the strength input covers all of them.
Last reviewed: October 2026. Numbers that drift (fees, prices, densities) are editable inputs on this page.
Pool bleach FAQs
How many gallons of bleach to shock a pool?
"Shock" is just a big FC rise — typically to 10–30 ppm depending on CYA. Run the calculator with current FC and your shock target: a 15,000 gal pool at CYA 40 shocking from 2 to 16 ppm with 10% takes about 2.2 gallons, split into two evening additions.
Is pool-store liquid chlorine better than household bleach?
Same chemical. Per available chlorine, 10–12.5% liquid chlorine usually beats household bleach on price at pool quantities, but plain 8.25% unscented bleach from any grocery store is completely legitimate — just check the label for additives and adjust the % here.
Why did my FC not rise as much as calculated?
Usually one of three: the sun burned some off before you tested (dose at dusk), the pool is fighting algae consuming chlorine faster than the test can see, or the jug was old and weaker than its label. Re-test the next morning, not 20 minutes later.
Can I pour bleach into the skimmer?
Pour it into the pool itself, ideally in front of a return jet with the pump on. The skimmer pulls it concentrated past equipment, and if anything else was recently dosed into the skimmer, mixing happens where you cannot see it.