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. These calculators are for homeowners, renovators, builders, landscapers and tradespeople planning work on a house, yard or site, covering how much material an area will take, how a layout, slope or frame should be set out, and what size or capacity a room, tank or system needs before anything is bought or built. Enter your values below and the result updates instantly, and you can share a permalink that pre-fills the exact calculation. Measure the real space rather than working from nominal figures on a plan, and keep every length, area and volume in one unit system before entering it so feet and metres never get mixed. Where the result is material to buy, treat it as a starting figure and round up, because bags, sheets, rolls and panels come in fixed sizes and some of every order goes to offcuts, breakage and second coats; where the result is a dose, load or size rating, use it as calculated rather than padding it. 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. These are planning figures, not a structural, electrical or safety check. What a job actually consumes shifts with substrate porosity, compaction, ground conditions, waste and each product's own coverage or dose rating, so confirm the final quantity against the product details or with your supplier before ordering, and have any load-bearing, electrical, gas or drainage work designed and checked by a qualified professional.
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.