🧪 Chlorine Dosing Calculator
Enter your pool volume, current and target free chlorine, and which product you use to see exactly how much to add — no more guessing with the scoop or the jug.
💧 The Right Dose, Every Time
What is a Chlorine Dosing Calculator?
It tells you how much of a specific chlorine product to add to move your pool's free chlorine from where it is now to where you want it. Give it your volume, the current and target ppm, and your product type, and it applies that product's known dosing rate to return the exact amount.
Getting chlorine right is the single most important part of keeping water clear and safe, but the correct amount depends entirely on your pool's size and current reading. This removes the guesswork — dose with the pump running, let it circulate, and always re-test, treating the figure as a planning estimate.
❓ Frequently Asked Questions
What free chlorine level should I aim for?
For most residential pools a free chlorine (FC) level of 1–3 ppm is the everyday target, kept in proportion to your cyanuric acid (stabiliser) level. If the water is cloudy, algae is present, or after heavy use, you may shock to a much higher FC temporarily. Always test first, then dose toward the target this calculator gives.
What's the difference between the chlorine products?
Liquid chlorine (sodium hypochlorite, ~12.5%) adds no stabiliser and slightly raises pH. Cal-hypo (65%) is a strong granular shock but adds calcium hardness. Dichlor (56%) and trichlor (90%) are stabilised — convenient, but they steadily raise cyanuric acid, which can eventually lock up your chlorine, so watch that level over a season.
How does the calculator work out the amount?
Each product has a known dose to raise FC by 1 ppm per 10,000 gallons — for example about 10.7 fl oz of 12.5% liquid chlorine, or 2.0 oz of 65% cal-hypo. It multiplies that by how many ppm you're raising (target minus current) and by your pool volume in ten-thousands of gallons.
Can I add too much chlorine?
Yes — over-chlorinated water can irritate skin and eyes and shouldn't be swum in until FC drops back to a safe range. Add in measured amounts with the pump running, let it circulate, and re-test before adding more. Never mix chlorine products, and store them separately in a cool, dry place.