Pool Chemical Calculator
Your estimate
- Increase (ppm)
- 3
How much chlorine, baking soda, calcium or stabilizer to add — from your test results.
Updated 2026-10-20 · Based on: exact volume formulas (1 US gal = 3.785 L) and chemical strengths (1 ppm = 1 mg/L).
How to use the Pool Chemical Calculator
- Pick the chemical with the tabs: liquid chlorine, granular chlorine, alkalinity, calcium or stabilizer.
- Enter the pool volume in gallons.
- Enter the current level from your test kit and the level you want.
- Choose the product strength printed on the label and read the amount to add.
Formula
1 ppm in 10,000 gallons is 37.85 g (1.34 oz) of the pure chemical. The dose is divided by the product strength.
Liquid chlorine: trade percent = grams of chlorine per 100 mL, so 1 ppm in 10,000 gal takes 10.2 fl oz of 12.5 % chlorine or 21.3 fl oz of 6 % bleach.
Alkalinity (as CaCO₃): 1.68 parts of baking soda per ppm (1.4 lb per 10 ppm in 10,000 gal). Calcium hardness: 1.11 parts of calcium chloride ÷ purity. Stabilizer: 1 part cyanuric acid per ppm (13.4 oz per 10 ppm).
Worked example
With the values preset in the calculator above: (Liquid chlorine)
- Pool volume
- 15,000 gallon
- Current free chlorine
- 1 ppm
- Target free chlorine
- 4 ppm
- Liquid chlorine strength
- 12.5 % liquid chlorine
- Amount to add
- 46.1 fl oz (1,363 mL)
- Amount to add
- —
- Increase (ppm)
- 3
Ideal pool chemistry levels
- Free chlorine: 1–3 ppm in a plain chlorine pool; about 7.5 % of your CYA level when stabilized (3 ppm at 40 ppm CYA).
- pH: 7.4–7.6.
- Total alkalinity: 80–120 ppm (60–80 for salt pools).
- Calcium hardness: 200–400 ppm for plaster; 150–250 ppm for vinyl and fiberglass.
- Stabilizer (CYA): 30–50 ppm, 60–80 ppm for salt pools.
Doses per 10,000 gallons
- Raise chlorine 1 ppm: 10.2 fl oz of 12.5 % liquid chlorine or 2.1 oz of 65 % cal-hypo.
- Raise alkalinity 10 ppm: 1.4 lb of baking soda.
- Raise calcium 10 ppm: 1.2 lb of 77 % calcium chloride.
- Raise stabilizer 10 ppm: 13.4 oz of cyanuric acid.
Frequently asked questions
How much liquid chlorine for a 15,000 gallon pool?
To raise free chlorine from 1 to 4 ppm: 46.1 fl oz (1,363 mL) of 12.5 % liquid chlorine.
How much shock for a 20,000 gallon pool?
To reach about 10 ppm from 1 ppm: 2.31 lb of 65 % cal-hypo, or 1.44 gal (184 fl oz) of liquid chlorine.
How much baking soda to raise alkalinity?
1.4 lb per 10,000 gallons raises TA by 10 ppm. From 70 to 100 ppm in 15,000 gal: 6.31 lb.
How do I lower chlorine, alkalinity or stabilizer?
Chlorine falls on its own in sun. Alkalinity is lowered with muriatic acid and aeration. Stabilizer and calcium only go down by draining and refilling.
Can I add chemicals at the same time?
Add one at a time with the pump running, a few hours apart, and never mix chlorine with acid or two chlorine types in a bucket.
More calculators
Estimates only — check quantities with your supplier and local building code before you order.