How much liquid chlorine raises free chlorine?

About 10.7 fluid ounces of 12.5 percent liquid chlorine, or 13.4 fluid ounces of 10 percent, raises 10,000 gallons by 1 ppm of free chlorine. Scale up by the gallons and the ppm you want to add.

Does cal hypo or dichlor change other levels?

Yes. Cal hypo adds calcium hardness, and dichlor and trichlor add cyanuric acid (stabilizer) and lower pH. Liquid chlorine and bleach add only chlorine and a little salt, so they are the cleanest for routine dosing.

What is shocking a pool?

Shocking means raising the free chlorine to a high level, often around 10 to 12 ppm or to breakpoint, to kill algae and clear combined chlorine. Set the target high in the calculator to find the shock dose.

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Pool Chlorine Calculator

A pool chlorine calculator tells you how much chlorine to add. It takes your pool gallons, the current and target free chlorine, and the product, and returns the dose in the right unit. Enter your numbers below. Everything runs in your browser, with no signup.

Updated for 2026

Your pool and target

Enter the gallons and the levels. Results update instantly.

Chlorine product

Pool volume

gal

Current free chlorine

ppm

Target free chlorine

ppm

Chlorine to add

Raise needed

0 ppm

Product

In common units

Also adds

Add chlorine gradually and re test before swimming

Always follow the product label.

Chlorine dose by product

Amount to raise 10,000 gallons by 1 ppm of free chlorine. Tap a row to load that product.

Product	Strength	Per 10k gal / ppm	Also adds

How the chlorine dose is calculated

Each product has a base dose to raise 10,000 gallons by 1 ppm of free chlorine. Scale it by your gallons and the parts per million you want to add:

Dose = Base dose × ( Gallons ÷ 10,000 ) × ( Target − Current )

About 10.7 fluid ounces of 12.5 percent liquid chlorine raises 10,000 gallons by 1 ppm. Granular products are measured by weight: roughly 1.8 ounces of 73 percent cal hypo does the same. Cal hypo adds calcium, and dichlor and trichlor add stabilizer and lower pH, so liquid chlorine is the cleanest for routine dosing.

Worked example (Stand: 2026)

Pool20,000 gallons
Current free chlorine1 ppm
Target free chlorine3 ppm
Raise needed2 ppm
Product12.5% liquid (10.7 oz base)
Dose (10.7 × 2 × 2)42.8 fl oz
In common unitsabout 1.3 quarts

Frequently asked questions

How much chlorine do I add?

It depends on gallons, the raise needed, and the product. The calculator above scales the base dose by your gallons and the ppm you want to add, and shows the amount in the product unit plus a common measure.

How much liquid chlorine per ppm?

About 10.7 fluid ounces of 12.5 percent liquid raises 10,000 gallons by 1 ppm, or 13.4 fluid ounces of 10 percent. Scale by your gallons and ppm.

Does cal hypo or dichlor add other things?

Yes. Cal hypo adds calcium hardness, and dichlor and trichlor add cyanuric acid stabilizer and lower pH. Liquid chlorine adds only chlorine and a little salt.

How do I shock the pool?

Set a high target, often 10 to 12 ppm, to find the shock dose. Add it in the evening and let the chlorine work overnight, then retest before swimming.

Does this calculator store my numbers?

No. Everything is calculated in your browser. Nothing you enter is sent to a server or saved.

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