How to Use the Pool Chlorine Dosage Calculator
Filling up a backyard kiddie pool or hot tub for the season means keeping the water sanitized with chlorine โ but every product (bleach, liquid pool chlorine, cal-hypo granules) has a different available-chlorine concentration, making "how much do I add?" hard to answer by eye. This calculator takes your water volume, target chlorine increase in ppm, and product type, and gives you the exact dose.
The math follows the standard pool-chemistry approach: ppm is milligrams of chlorine per liter (or, in imperial terms, pounds per million pounds of water). Multiplying your target ppm by the water volume gives the pounds of pure chlorine needed; dividing that by your product's percent concentration gives the actual amount of product to add. Household bleach (~5%) needs a much larger volume than pool-grade liquid chlorine (~12%) or cal-hypo granules (~65%) to hit the same target.
A target of 1-3 ppm free chlorine is typical for home pools and hot tubs โ lower risks weak disinfection, higher risks skin and eye irritation. Since chlorine doesn't distribute instantly, run the pump for 30-60 minutes after dosing, then confirm the level with a test strip before anyone gets in. Never mix bleach with other cleaning chemicals โ the combination can produce toxic gas.
Frequently Asked Questions
For home pools and hot tubs, 1-3 ppm is a typical target. Too low and disinfection is weak; too high and it can irritate skin and eyes.
No โ the chlorine needs time to circulate and react throughout the water. Run the pump for 30-60 minutes, then test the level with a test strip before swimming.