Pool Chlorine Dose Calculator
The Pool Chlorine Dose Calculator computes pool chlorine dose from the relation product pounds = ppm increase x gallons x 8.34 / 1,000,000 / (available chlorine percent / 100). It takes 3 inputs (free chlorine increase wanted in ppm, pool water volume in gallons, available chlorine in product in %) and returns the pool chlorine dose. Because this is a pure mathematical or physical formula rather than a jurisdiction-specific rule, the result never changes over time: the same inputs always produce the same answer, so you can rely on it whether you are checking homework, sizing a design, or sanity-checking another tool. Enter your values in the fields below and the result updates instantly; you can also share a permalink that pre-fills the exact calculation, which is useful for teaching, reports, or collaboration. For example, with free chlorine increase wanted = 5 ppm, pool water volume = 20000 gallons, available chlorine in product = 65 %, the pool chlorine dose works out to 1.283077, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by U.S. Centers for Disease Control and Prevention: Healthy Swimming, and the figure above each result carries the date it was last verified. This tool is general information and is not a substitute for professional engineering, medical, financial, or scientific advice; always check critical results against the primary source and your own judgement.
With Free chlorine increase wanted = 5 ppm, Pool water volume = 20000 gallons, Available chlorine in product = 65 %, the result is 1.283077.
Applies to: any numeric inputs. Method source: U.S. Centers for Disease Control and Prevention: Healthy Swimming, checked 2026-06-23.
The formula
product pounds = ppm increase x gallons x 8.34 / 1,000,000 / (available chlorine percent / 100)
Worked example
With Free chlorine increase wanted = 5 ppm, Pool water volume = 20000 gallons, Available chlorine in product = 65 %:
- Pure chlorine pounds = ppm x gallons x 8.34 / 1,000,000
- Product pounds = pure / (available percent / 100) = 1.2831 lb
- Pool Chlorine Dose = 1.283077
This worked example is one of the automated golden-value tests this calculator must pass before it can publish.
What this assumes
- Inputs are real numbers in the units shown.
- The result is the exact value of product pounds = ppm increase x gallons x 8.34 / 1,000,000 / (available chlorine percent / 100); general information, not professional advice.
Frequently asked questions
What formula does this use?
product pounds = ppm increase x gallons x 8.34 / 1,000,000 / (available chlorine percent / 100), the standard form documented by U.S. Centers for Disease Control and Prevention: Healthy Swimming.
Does the result ever change over time?
No. This is a pure formula with no external rate, so the same inputs always give the same result.
Official sources and verification
- Method: U.S. Centers for Disease Control and Prevention: Healthy Swimming, checked 2026-06-23.
Reviewed by the CalculatorHub team, edited by James Graham, 2026-06-23. See our methodology. General information, not professional advice.