Enter your pool volume and where free chlorine is now. The dose comes from the same engine as the PoolDose app — including the split-dose limits and side effects most calculators skip.
The long version — with the numbers for every product — is in the chlorine dosage chart.
Raising 10,000 gallons by 1 ppm takes about 37.9 g of available chlorine. The calculator scales that by your volume and the ppm gap, then divides by the strength of the product you picked. Doses are rounded down — adding a little less and retesting beats overshooting.
Amounts above the safe single-addition limit are split into stages, with a retest between each. That limit is per 10,000 gallons and depends on the product.
This page does one parameter. The PoolDose app does the same calculation for pH, alkalinity, calcium, CYA, salt and bromine — offline, with your own products and their real strengths saved. One-time purchase, no subscription, no account.