Pool chemical cost calculator
Compare chlorine by cost per ppm, not price per jug.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (7 sections)
Raising free chlorine (FC) 1 ppm in 10,000 gallons takes 10.24 fl oz of 12.5% liquid chlorine or 1.48 oz of 90% trichlor.
Cal-hypo at 65% takes 2.05 oz. In the example below (15,000 gallons, $6 a gallon, 2 ppm used per day), 12.5% liquid chlorine costs $0.72 per ppm for the whole pool, about $10 a week.
About these numbers. The amount of product per ppm comes from our tested chlorine formulas. The cost arithmetic on top of it is not yet covered by reference tests, and the $6 price and 2 ppm per day are example values, not market data. Enter what you actually pay and what your pool actually uses.
Calculator: enter prices you pay
Pick the product, its strength, the price, and the package size (gallons, fl oz, lb, or oz), then your daily chlorine use. To measure daily use, test FC at dusk, add nothing overnight or the next day, and test again at the next dusk. Rain, heavy swimming, and heat raise the number.
Cost per ppm per 10,000 gal
Here is how much of each product it takes to add 1 ppm in 10,000 gallons, and the multiplier that turns your price into a cost per ppm. Cal-hypo is calcium hypochlorite, CYA is stabilizer (cyanuric acid), and TA is total alkalinity.
| Product | Amount | Cost per ppm per 10,000 gal | Side effect per 1 ppm FC |
|---|---|---|---|
| Liquid chlorine 12.5% | 10.24 fl oz | 0.080 × price per gallon | none that builds up (adds a little salt) |
| Liquid chlorine 10% | 12.8 fl oz | 0.100 × price per gallon | same |
| Household bleach 8.25% | 14.5 fl oz | 0.113 × price per gallon | same; use plain, unscented |
| Household bleach 6% | 20.61 fl oz | 0.161 × price per gallon | same |
| Trichlor tablets 90% | 1.48 oz | 0.093 × price per lb | +0.6 ppm CYA; lowers TA about 0.7 ppm |
| Cal-hypo 65% | 2.05 oz | 0.128 × price per lb | +0.7 ppm calcium hardness |
| Cal-hypo 73% (about 70% available) | 1.91 oz | 0.119 × price per lb | +0.7 ppm calcium hardness |
| Dichlor 56% | 2.38 oz | 0.149 × price per lb | +0.9 ppm CYA |
Liquid chlorine by trade %, bleach by % sodium hypochlorite by weight, as labels state them. For jugs sold in fl oz: cost per ppm = amount ÷ jug size × jug price.
Example: if 12.5% liquid chlorine costs $6 a gallon, 1 ppm in 10,000 gallons costs 0.080 × $6 = $0.48, and in 15,000 gallons 1.5 × $0.48 = $0.72. To choose a chlorine type on more than price, see types of pool chlorine.
Hidden costs: CYA build-up from tablets means draining
Price per ppm makes trichlor tablets look cheap. The catch is stabilizer: every 1 ppm of chlorine from trichlor adds 0.6 ppm of cyanuric acid (CYA), and CYA leaves only when water does. Over a season it adds up fast:
| Chlorine used per day | After 100 days | After 150 days |
|---|---|---|
| 1 ppm | +60 ppm CYA | +90 ppm CYA |
| 2 ppm | +120 ppm CYA | +180 ppm CYA |
| 3 ppm | +180 ppm CYA | +270 ppm CYA |
High CYA means you need more free chlorine for the same disinfecting power, and eventually the fix is draining. Bringing CYA from 150 down to 50 ppm with stabilizer-free fill water means replacing about 67% of the water (from 100 ppm: 50%). That water, plus rebalancing chemicals, belongs in the tablet column of your budget. The pool fill cost calculator prices it. If you like tablets, one way to limit the build-up is to use them only until CYA reaches your target, then switch to liquid chlorine. The chlorine tablet calculator projects the build-up week by week for your pool.
Liquid chlorine has its own hidden cost: it weakens in storage. PHTA reports that 12.5% sodium hypochlorite loses half its strength in about 180 days at 77 °F and in about 48 days at 95 °F. A jug left in a hot garage for a summer delivers less than its label, so you pay for chlorine you never get.
Season cost estimate
Season cost = cost per ppm (for your pool) × ppm used per day × days in the season. With the calculator's example ($0.72 per ppm, 2 ppm a day), a 150-day season comes to about $216 in chlorine. At 3 ppm a day it would be about $324. Your real figure depends on sun, CYA, swimmers, and whether you use a cover. A salt chlorinator changes the math completely. See salt vs chlorine costs.
Buying tips
- Compare per ppm, then per season. A cheaper bucket that forces a partial drain in August is not cheaper.
- Buy liquid chlorine fresh and store it cool and shaded. Don't stock up for a whole summer unless you have a cool place for it.
- Check the percent on the label. Bleach sold at 6% needs roughly 60% more volume than 10% pool chlorine per ppm (20.61 vs 12.8 fl oz per 10,000 gallons). Use the bleach dose calculator or the liquid chlorine calculator for exact doses.
- Keep CYA in range (30–50 ppm for hand-chlorinated pools) so you don't need extra chlorine to make up for it.
- Cover the pool when you can: the DOE says covers cut chemical use by 35–60%.
FAQ
Why is pool chlorine so expensive?
Prices depend on supply, season, and region. One well-documented example: in August 2020, a fire at BioLab's Lake Charles, Louisiana, plant after Hurricane Laura shut down a major source of chlorine tablets, and industry press blamed it in part for the 2021 shortage. Whatever the price, comparing cost per ppm and storing liquid chlorine cool helps you get more from each dollar.
Is liquid chlorine cheaper than tablets?
Per ppm, it depends on your local prices. Use the multipliers above. Per season, tablets often cost more than they appear, because the stabilizer they add builds up and eventually requires draining and refilling part of the pool.
How much does it cost to maintain a pool per month?
For chlorine alone: cost per ppm × ppm used per day × 30. In the example above, $0.72 × 2 × 30 is about $43 a month. Add acid, occasional stabilizer or calcium, test supplies, pump electricity, and any heating. The heater cost calculator covers heating.
Sources
- PHTA fact sheet, Sodium hypochlorite (trade percent, decomposition): phta.org
- U.S. DOE Energy Saver, Swimming pool covers (chemical savings; archived copy, May 2026): energy.gov via web.archive.org
- BIC Magazine, Lake Charles fire partly to blame for chlorine shortage: bicmagazine.com
- Chlorine dose formulas, side effects (PHTA: trichlor 0.6 ppm CYA, dichlor 0.9 ppm CYA per 1 ppm FC) and reference tests: methodology