Pool chemical calculator.
Work out pool volume, chlorine or shock dosage, salt additions and water replacement from the numbers you actually have.
Chlorine or shock dosage
Enter the pool volume and the free-chlorine change you want. The result shows the amount of product, not just a ppm target.
Salt addition or water replacement
Use your salt-system manufacturer's target. If the pool is already too salty, the calculator estimates the fraction of water to replace.
Pool volume
Choose the closest shape and enter the average water depth. For a sloped pool, use the shallow and deep measurements.
See the numbers behind the answer.
The calculator converts your pool into litres, applies the change in parts per million, then adjusts for the strength or purity of the product you selected. That means you can check the assumptions instead of trusting a mystery recommendation.
For chlorine, the result is based on the amount of available chlorine needed. For salt, it uses the difference between current and target concentration. If the target is lower than the current reading, it switches to a water-replacement estimate.
How accurate is the result?
It is only as accurate as your pool volume, test reading and product label. Irregular shapes, ageing chemicals and inaccurate test kits can change the real result, so retest after circulation and follow the label.
Which chlorine strength should I choose?
Choose the percentage printed on your product. Liquid chlorine strengths vary by brand and age; use the custom option if your label is different from the presets.
Why does salt need a target?
Salt-water chlorinators do not all use the same operating range. Enter the target from your specific generator's manual rather than relying on a generic number.