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Pool Chlorine Dose Calculator

Work out the chlorine needed to raise free chlorine to a target, for the product you actually have.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Product required

0.17 gal

Check your inputs

The dose arithmetic is reliable; the pool volume usually is not. Add, circulate, then retest rather than dosing twice from a calculation.

Rise required
1.5 ppm
Pure available chlorine
75 g
Product
625 g
Pool volume
13208.6 gal
US gallons
13208.6 gal

Running these inputs gives 0.63 litres as the product required. Note that pool volume and current free chlorine (ppm) sit at the edge of the range this calculator was checked against, so treat the output as indicative rather than settled. Expect some drift against the real job; the calculation is solid but conditions on site are not. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Recommended free chlorine 1-3 ppm for residential pools — CDC Model Aquatic Health Code and WHO guidance
  • 1 ppm = 1 g per 1000 L. Product strengths: sodium hypochlorite 10-15% available chlorine; cal hypo 65-73%; dichlor 56%; trichlor 90%

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why does my chlorine disappear so fast?
Usually sunlight. Ultraviolet destroys unstabilised chlorine within hours — an outdoor pool can lose most of its free chlorine in a day. Cyanuric acid at 30-50 ppm protects it. Above roughly 100 ppm the same acid starts locking the chlorine up instead, which is the other end of the same problem.
Which product should I use?
Liquid for routine dosing if you can store it and use it fresh — it adds nothing that accumulates. Cal hypo where hardness is low. Dichlor and trichlor are convenient and add cyanuric acid with every dose, which is fine until it is not; test for it a few times a season.
Why retest instead of dosing twice?
Because the pool volume is almost always an estimate, and the error compounds. Add the calculated dose, run the pump for a full turnover, then test. Two calculated doses in a row is how pools end up far above target.