How It Works
This calculator works in 4 steps.
Compute the pool volume
Type length, width, and average depth, or enter gallons or liters directly.
Enter the product data
Type the available chlorine percent, or the label dose per 10,000 gallons per ppm.
Enter the ppm change
Type the current and target levels, such as 1 ppm to 3 ppm.
Read the product amount
The calculator returns product in fl oz, mL, lb, or g, with the label's addition steps.
The Formula
The formula multiplies pool volume by the ppm change and divides by the product's active concentration.
gal = L (ft) × W (ft) × avg depth (ft) × 7.48g = V (L) × Δppm / 1,000mL = g active / (g per L of product) × 1,000- Δppm:
- Change in level (mg/L)
- V:
- Pool volume
- g per L of product:
- Available chlorine per liter, 125 g/L at 12.5%
A 32 × 16 ft pool with an average depth of 5 ft holds 32 × 16 × 5 × 7.48 = 19,149 gallons. Raising free chlorine by 1 ppm with 12.5% liquid chlorine takes about 580 mL (19.6 fl oz).
Conversion Table
The conversion table gives the amount of 12.5% liquid chlorine that raises free chlorine by 1 ppm in 5 pool volumes.
| Pool volume | Chlorine needed (1 ppm) | 12.5% liquid (mL) | 12.5% liquid (fl oz) |
|---|---|---|---|
| 5,000 gal (18.93 m³) | 18.93 g | 151.4 mL | 5.12 fl oz |
| 10,000 gal (37.85 m³) | 37.85 g | 302.8 mL | 10.24 fl oz |
| 15,000 gal (56.78 m³) | 56.78 g | 454.2 mL | 15.36 fl oz |
| 20,000 gal (75.71 m³) | 75.71 g | 605.7 mL | 20.48 fl oz |
| 30,000 gal (113.6 m³) | 113.6 g | 908.5 mL | 30.72 fl oz |
Assumes 125 g/L available chlorine. Product strength drops with age; follow the label for dosing and safety.
What Is the Pool Chemical Dilution Calculator?
The Pool Chemical Dilution Calculator is a tool that scales a pool product's label instructions to the pool's water volume and the desired change in level, such as raising free chlorine by 2 ppm. The calculator first finds the pool volume, then multiplies the product's dose per unit volume by the ppm change.
Pool chemicals differ in strength: liquid chlorine (sodium hypochlorite) is sold at about 10% to 12.5% available chlorine, and calcium hypochlorite granules at about 65% to 73%. The calculator uses the strength and dose rate printed on the product, and it prints the label's pre-dissolving and addition steps. Pool chemicals are never mixed with each other before adding to water.
Common Uses
There are 5 main uses of this calculator.
Chlorine dosing
Pool owners raise free chlorine to a target level.
Shock treatment
Operators scale the label shock dose to pool volume.
pH adjustment
Users scale acid or soda ash doses from the label.
Stabilizer dosing
Owners add cyanuric acid to a target ppm.
Spa and hot tub care
Users scale small-volume doses for 300 to 500 gallon tubs.