Pool Chlorine Calculator
Dose liquid chlorine, tablets or shock for your pool volume.
Enter your values
Enter the pool volume in gal.
Enter the current free chlorine in ppm.
Enter the target free chlorine in ppm.
Choose one of: Liquid chlorine 12.5%, Cal-hypo 68% (oz), Dichlor 56% (oz).
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Dose needed
- 32.1 fl oz
- In cups / pounds
- 4.01 cups
- Chlorine rise
- 2 ppm
- Shock dose (to 10 ppm)
- 1.25 gallons of liquid chlorine
Working
- 115,000 gal / 10000 x 2 ppm x 10.7 = 32.1
Quick answer
To raise chlorine by 1 ppm in 10,000 gallons you need about 10.7 fl oz of 12.5% liquid chlorine, or 2 oz of 68% cal-hypo.
dose = gallons / 10000 x ppm rise x product factor
At a glance
| What it does | Dose liquid chlorine, tablets or shock for your pool volume. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Pool volume, Current free chlorine, Target free chlorine, Product |
| Main output | Dose needed |
| Formula | dose = gallons / 10000 x ppm rise x product factor |
| Cost | Free — no sign-up, no download |
How to use the Pool Chlorine Calculator
- 1Test the water and enter the current free chlorine reading.
- 2Set your target - 2 to 4 ppm for most pools, higher if cyanuric acid is high.
- 3Add the dose with the pump running and re-test after an hour of circulation.
Inputs explained
- Pool volume(gal)
- Enter the pool volume in gal.
- Current free chlorine(ppm)
- Enter the current free chlorine in ppm.
- Target free chlorine(ppm)
- Enter the target free chlorine in ppm.
- Product
- Choose one of: Liquid chlorine 12.5%, Cal-hypo 68% (oz), Dichlor 56% (oz).
Worked example
Using the values the calculator loads with:
Inputs
- Pool volume15000 gal
- Current free chlorine1 ppm
- Target free chlorine3 ppm
- ProductLiquid chlorine 12.5%
Results
- Dose needed32.1 fl oz
- In cups / pounds4.01 cups
- Chlorine rise2 ppm
- Shock dose (to 10 ppm)1.25 gallons of liquid chlorine
- 15,000 gal / 10000 x 2 ppm x 10.7 = 32.1
Frequently asked questions
Why does my chlorine disappear so fast?
Usually low cyanuric acid (no UV protection), high bather load or an algae bloom eating the chlorine as fast as you add it.
Liquid chlorine or tablets?
Tablets are convenient but add cyanuric acid every time. Liquid chlorine adds none, which is why most pool pros use it in summer.
What do I need to enter into the Pool Chlorine Calculator?
Just 4 values: pool volume, current free chlorine, target free chlorine, product. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Pool Chlorine Calculator work out the answer?
To raise chlorine by 1 ppm in 10,000 gallons you need about 10.7 fl oz of 12.5% liquid chlorine, or 2 oz of 68% cal-hypo. It applies the formula dose = gallons / 10000 x ppm rise x product factor and shows the working so you can check each step by hand.
Is the Pool Chlorine Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.