Free · No sign-up · Every formula published
Pool Water Calculator is a free swimming pool calculator suite. Find your pool’s exact volume, turn test results into chemical doses, add the right amount of salt, and price a new inground pool, all with the math shown.
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Every dose on this site starts with one number: how many gallons your pool holds. Enter length, width and the shallow and deep end depths for rectangle, round, oval or kidney pools, and get US gallons, liters and cubic meters instantly. Your result is saved on this device, so every other calculator prefills it.
Type in your test results for free chlorine, pH, alkalinity, calcium hardness and stabilizer, and get the exact amount of each product to add, in the order that keeps one adjustment from undoing another. Doses are based on the strength printed on your label.
Find how many pounds and bags of salt bring a saltwater pool up to the level your chlorinator wants, whether you are starting a new pool or topping up after rain.
Compare concrete, fiberglass and vinyl liner pools with national price ranges from published cost guides, then add heaters, fencing, covers and decking.
Plain-English guides to ideal chemistry levels, accurate testing, and fixing green or cloudy water, written to answer the questions owners actually ask.
How it works
Most dosing mistakes come from guessing the pool size or adding chemicals in the wrong order. Work through these in sequence and retest between adjustments.
Not sure what a reading should be? The pool chlorine calculator shows the right free chlorine for your stabilizer level, and the above-ground pool gallons by size table covers standard round and oval pools.
Get your gallons from the volume calculator. It is saved for every other tool.
Test free chlorine, pH, alkalinity, calcium and stabilizer with a reliable kit.
Alkalinity, then pH, calcium, stabilizer and chlorine. Add half, circulate, retest.
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The amounts most owners look up every week, calculated for a 10,000-gallon pool. Double them for 20,000 gallons, halve them for 5,000.
| Change | Product | Amount |
|---|---|---|
| Raise FC 1 ppm | Liquid chlorine 10% | 12.8 fl oz |
| Raise TA 10 ppm | Baking soda | 1.4 lb |
| Raise CH 10 ppm | Calcium chloride 77% | 1.2 lb |
| Raise CYA 10 ppm | Stabilizer | 13.4 oz |
| Lower pH 7.8 → 7.5 (TA 80) | Muriatic acid 31.45% | 8.8 fl oz |
| Raise salt 0 → 3,200 ppm | Pool salt | 267 lb |
Multiply length × width × average depth (in feet) × 7.48 for a rectangular pool. For a round pool use diameter × diameter × average depth × 5.9. Average depth is the shallow end plus the deep end divided by two. A 16 × 32 ft pool averaging 5.5 ft deep holds about 21,065 gallons.
A pool needs a sanitizer (free chlorine) plus balanced pH (7.2–7.8), total alkalinity (about 60–120 ppm), calcium hardness (about 200–400 ppm) and stabilizer (about 30–50 ppm, or 60–80 ppm in salt pools). Use the pool chemical calculator to turn your test results into doses.
In 10,000 gallons, about 12.8 fl oz of 10% liquid chlorine or 10.2 fl oz of 12.5% liquid chlorine raises free chlorine by 1 ppm. Cal-hypo 65% takes about 2 oz by weight. Scale the amount with your pool volume.
Raising 10,000 gallons from 0 to 3,200 ppm takes about 267 lb of salt, roughly seven 40 lb bags. The formula is ppm increase × gallons × 8.34 ÷ 1,000,000. Always use the target range in your chlorinator manual.
Yes. Every calculator is free with no sign-up, and the math is covered by automated tests. All formulas, constants and sources are published on the methodology page so you can check any result yourself. Results are estimates, so add chemicals in stages and retest.
Published cost guides put most inground pools between about $25,000 and $120,000 installed. Vinyl liner pools sit at the low end, fiberglass in the middle, and concrete (gunite) at the high end, before add-ons like fencing, heating and decking.
Every formula, constant and source behind these calculators is published, from 7.48 gallons per cubic foot to the buffer model behind our acid doses.