Pool chemistry calculators for home pools
Work out your pool's volume and your chlorine or shock dose for your backyard pool, with every step of the math and its source shown. For home swimming pools only, not beaches, lakes or open water.
Pool volume calculator
Gallons and litres for rectangle, round, oval and sloped pools. The starting point for every dose.
Chlorine and shock calculator
Liquid chlorine, cal-hypo, dichlor or trichlor: daily top-up, breakpoint or the shock dose on your label, with side effects on stabilizer and calcium.
Liquid chlorine strength explained
Why “12.5 %” can mean two strengths, and what it does to your dose.
Why trust the numbers?
Every formula is a unit definition (NIST), comes from a primary source, or is our own documented calculation; the methodology page says which. Each calculator is tested against published worked examples, and we list every test case, including the ones where sources disagree, on the methodology page.
Disclaimer: GoodToSwim.com gives estimates for home (residential) chlorine pools based on published primary sources. It does not cover spas, hot tubs or bromine, and it does not report water quality at beaches, lakes, rivers or other open water. It never tells you that your water is safe to swim in. Results depend on your test accuracy, your pool volume and the real strength of your product. They do not replace the product label, local health regulations or a qualified pool professional. Public and commercial pools must follow local code.