Pool Chemical Calculator
Calculate chlorine, shock, algaecide, and pH adjuster amounts needed for your pool volume in gallons or liters.
Covers above-ground and in-ground pools.
Enter your pool volume and desired chlorine level to calculate chemical amounts.
Pool chemicals are dosed based on pool volume and target concentration in ppm.
Chlorine dosing formula:
- Grams needed = (Volume in liters × Target ppm) / (% active chlorine × 10)
- Ounces needed = Grams / 28.3495
Common chlorine products:
| Product | Active Chlorine |
|---|---|
| Liquid bleach (12.5%) | 12.5% |
| Calcium hypochlorite | 65-73% |
| Sodium dichlor | 56-62% |
| Trichlor tablets | 90% |
Ideal chlorine levels:
- Free chlorine: 1-3 ppm (residential pools)
- Shock treatment: 10-30 ppm (superchlorination)
Pool volume estimation:
- Rectangular: Length × Width × Avg Depth × 7.48 (gallons) or × 1000 (liters if in meters)
- Round: Diameter² × Avg Depth × 5.9 (gallons)
Volume conversions:
- 1 US gallon = 3.785 liters
- 1,000 gallons = 3,785 liters
To raise chlorine by 1 ppm in 10,000 gallons:
- Liquid bleach (12.5%): ~10 fl oz (296 mL)
- Cal-hypo (65%): ~2 oz (57 g)
- Trichlor (90%): ~1.5 oz (43 g)
The strength differences in that list matter more than they look, because they change how much you pour. Liquid chlorine is only 10 to 12.5% available chlorine, while cal-hypo granular is 65 to 73%, so you need roughly five times less of the granular for the same effect. Dose by the percentage, not by habit, or you’ll wildly over- or under-treat the water.
Two things trip up new pool owners. First, cyanuric acid (stabilizer) protects chlorine from sunlight, but too much of it locks the chlorine up so it stops sanitizing, the dreaded “chlorine lock” where your test shows chlorine present yet the water still goes green. The only real fix is diluting with fresh water. Second, never mix pool chemicals together, and never pour water into acid; always add acid to water, slowly, and ideally treat in the evening so the sun doesn’t burn off the chlorine before it works. Test first, dose once, retest the next day, and resist the urge to dump everything in at once.
How we build and check this converter
This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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