Pool Chemical Calculator (USA)
Enter your pool volume and test results to see exactly how much chlorine, acid, alkalinity, calcium, stabilizer and salt to add to reach ideal ranges, plus a water report card and a printable PDF dosing plan.
| Parameter | Current | Target | Recommended | Amount |
|---|---|---|---|---|
| Calculate to see the dosing plan | ||||
Highlighted rows need an adjustment. Add chemicals one at a time with the pump running, then retest before the next addition. Lowering pH also lowers alkalinity, and adding dichlor or cal-hypo also raises stabilizer or calcium.
How to Use the Pool Chemical Calculator
Turn a test strip reading into an actual shopping list — how much of what to add, in ounces, pounds and gallons — in four steps.
Enter your pool volume
Every dose scales directly from gallons, so start here. Then pick chlorine or saltwater — saltwater adds a salt level to the test panel and the dosing plan.
Choose your chlorine product
Liquid chlorine, cal-hypo or dichlor. Each has a different strength and a different side effect, and the note under the buttons tells you what else that product adds to the water.
Type in your test results
Free chlorine, pH, total alkalinity, calcium hardness and stabilizer, straight off your kit or strip. The report card flags each one as low, on target or high as you type.
Set targets and get the plan
Adjust the target levels if your pool runs differently, then read the doses. Download the two-page PDF and take the dosing plan out to the equipment pad with you.
What’s Included
Six levels, one plan — with the amount named in the units on the bottle, not in parts per million you still have to convert.
Chlorine dose by product
Switch between liquid 12.5%, cal-hypo 73% and dichlor 56% and the amount changes with the strength — in fluid ounces, quarts, gallons or pounds as the number gets bigger.
pH up and pH down
Soda ash to raise pH, muriatic acid to lower it — and the acid dose accounts for your alkalinity, because a high-TA pool resists a pH change far more than a low-TA one.
Alkalinity and hardness
Baking soda to bring total alkalinity up, calcium chloride for hardness, and an honest answer when a level is too high to fix with a product — drain and dilute.
Stabilizer and salt
Cyanuric acid to protect chlorine from the sun, and — in saltwater mode — pool salt in pounds and 40 lb bags to bring a low cell reading back up to range.
Water report card
Every level tagged low, OK or high at a glance, a bar chart showing each reading as a percentage of its target, and a donut summarising how balanced the water is overall.
Printable dosing plan
A two-page PDF with your test summary, report card, the full parameter-by-parameter dosing table with the rows that need action highlighted, and safety reminders.
By the Numbers
A quick snapshot of what the calculator balances and the ranges it works toward.
chlorine through salt
liquid, cal-hypo, dichlor
the range most pools target
chlorine or saltwater
no sign-up needed
Built for “The Strip Says Low — Now How Much?”
Test kits tell you where the water is. Product labels tell you a dose per 10,000 gallons. This is the arithmetic in between.
Weekly maintainers
Testing every few days and topping up chlorine and acid. Enter the readings, get the amounts, and stop eyeballing the scoop or the jug.
Cloudy-water troubleshooters
Chlorine that won’t hold, water that turns green after a storm, a pH that keeps drifting up. Seeing all six levels side by side usually shows which one is the cause.
Saltwater pool owners
Salt cells still need balanced water, and a low salt reading has a specific fix. Switch to saltwater mode for salt in pounds and bags alongside everything else.
Add One Thing, Wait, Then Test Again
Seven habits that keep pool chemistry boring — which is exactly what you want it to be.
- 1Get the volume right first. Every dose here is scaled from gallons, so a volume that’s off by a quarter puts every chemical you add off by a quarter. Calculate it once from your pool’s real dimensions and average depth, then write it somewhere permanent.
- 2Trust a drop test over a strip. Strips are quick but drift with age, heat and how long you dunk them. A liquid reagent kit costs more once and gives you numbers worth dosing against — and no calculator can be more accurate than the reading you feed it.
- 3Fix alkalinity before you chase pH. Total alkalinity is what stops pH bouncing around. If TA is low, pH will swing after every addition and you’ll be adding acid every few days — get TA into range first and pH usually settles on its own.
- 4Remember that acid lowers both. Muriatic acid brings pH down and alkalinity down together, so you can’t move one without touching the other. Lowering TA is done by adding acid and then aerating the water to bring pH back up — repeat rather than dumping in a large dose.
- 5Watch what your chlorine sneaks in. Dichlor and trichlor add stabilizer with every dose, cal-hypo adds calcium, and liquid chlorine adds neither. Use pucks all season and CYA climbs quietly until your chlorine stops working at levels that used to be fine.
- 6Some levels only come down with water. Cyanuric acid, calcium hardness and salt have no practical reducer — the fix is draining part of the pool and refilling with fresh water. That’s why overshooting them costs far more than undershooting.
- 7One chemical at a time, pump running. Never mix products in a bucket or pour one on top of another, and always add chemical to water rather than water to chemical. Dose, circulate, wait the time the label states, then retest before the next addition.
Frequently Asked Questions
Answers to the most common questions about chlorine doses, pH, alkalinity, stabilizer and salt.
How much chlorine do I need to add to my pool?
It depends on how far your free chlorine is below target, your pool volume and which product you’re using. As a rough guide, raising free chlorine by 1 ppm in 10,000 gallons takes roughly 11 fluid ounces of liquid chlorine at 12.5%, about 2 ounces of cal-hypo at 73%, or about 2.7 ounces of dichlor at 56%. So a 20,000-gallon pool going from 1 ppm to 3 ppm needs roughly a quart and a half of liquid chlorine. Enter your own readings and the calculator does the arithmetic for whichever product you’ve selected.
How do I raise or lower the pH in my pool?
Soda ash raises pH; muriatic acid lowers it. Most pools aim for somewhere between 7.4 and 7.6, where chlorine works efficiently and the water isn’t aggressive toward plaster or equipment. The acid dose isn’t a fixed number — a pool with high total alkalinity resists a pH change much more than one with low alkalinity, so the same drop takes more acid. Add acid in a slow stream over a return with the pump running, never all in one spot, and retest after the water has circulated rather than immediately.
How much baking soda raises pool alkalinity?
About 1.5 pounds of baking soda per 10,000 gallons raises total alkalinity roughly 10 ppm. A 20,000-gallon pool going from 70 ppm to 100 ppm therefore needs somewhere around 9 pounds. Baking soda nudges pH up slightly as well, which is usually welcome when alkalinity is low. Spread it around the pool with the pump running and give it several hours before retesting — dumping the whole amount in one place tends to leave a cloudy patch and a misleading reading.
Should I adjust pH or alkalinity first?
Alkalinity first, because it’s what keeps pH stable. With TA too low, pH swings after every addition and you’ll never get it to settle; with TA in range, pH tends to hold. The two are linked in both directions, though — acid lowers pH and alkalinity together, and aerating the water raises pH without changing alkalinity, which is how you bring a high TA down while holding pH steady. Once both are in range, move on to chlorine, then stabilizer and hardness.
How do I lower cyanuric acid (stabilizer)?
By replacing water. There’s no everyday product that reduces cyanuric acid, so the practical fix is draining part of the pool and refilling — draining a third cuts CYA by roughly a third. Raising it is easy by comparison: about a pound of stabilizer per 10,000 gallons adds somewhere near 12 ppm, and it dissolves slowly, so give it several days before retesting. CYA creeps up on its own if you chlorinate with pucks or dichlor, which is why a pool that suddenly can’t hold chlorine is often carrying far more stabilizer than the owner realises.
How much salt does a saltwater pool need?
Most salt chlorine generators want somewhere around 3,000 to 3,500 ppm, but the number that matters is the one in your cell’s manual. To work out the top-up, multiply the ppm you’re short by your gallons, multiply by 8.34 and divide by a million to get pounds — so raising a 20,000-gallon pool by 400 ppm takes roughly 67 pounds, or about two 40-pound bags. Salt only leaves through splash-out, backwashing and rain overflow, never through the cell, so top-ups are occasional. Add it with the pump running, brush it around, and wait until it has fully dissolved before trusting a reading.