Pool Unit Converter
Convert pool volumes, water temperatures, and chemical measurements instantly. Type in any box and the others update live. Every result is ready to use with the dosing calculators on this site, which all assume US gallons.
Volume
US gallons, liters, and UK (imperial) gallons. US dosing charts use US gallons.
Temperature
Comfortable swimming is about 78 to 82 F (26 to 28 C).
Weight (dry chemicals)
Cal-hypo, dichlor, soda ash, and baking soda are dosed by weight.
Liquid (pourable chemicals)
Muriatic acid and liquid chlorine are measured by volume.
Length
Measure pool dimensions in feet for US volume formulas.
Area (pool surface)
Surface area helps size covers, liners, and solar blankets.
ppm equals mg/L for pool water. A test reading of 3 ppm free chlorine is the same as 3 mg/L, so you never have to convert ppm itself, only the volume of water it is dosed into.
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One Page for Every Pool Conversion
Pool care is full of units that do not match up. Your liner came in feet, your heater reads Celsius, your shock is sold by the pound, and the acid you bought is poured by the cup. This converter keeps all of them in one place so you can move between systems without second-guessing the math. Type a number into any box and the related boxes update instantly, no button to press. Every formula here uses the standard conversion factors, so the results are ready to drop straight into the dosing tools on this site.
Volume: Get to US Gallons First
Volume is the single most important number in pool care, because every chemical dose is a concentration spread across your water. The catch is that a gallon is not always a gallon. A US gallon is 3.78541 liters, while a UK or imperial gallon is 4.54609 liters, about 20 percent larger. All of the dosing guidance on PoolCareCalculator.com, and on most US pool sites, assumes US gallons. If you live somewhere that sells pools and chemicals in imperial gallons or liters, convert to US gallons here before you trust a US chart, or simply do your math in liters and remember that 1 ppm equals 1 mg/L. Once you know your pool volume, write it down and reuse it for chlorine, salt, stabilizer, alkalinity, and shock.
Temperature: Fahrenheit and Celsius
Water temperature is comfort and chemistry at once. Comfortable swimming sits around 78 to 82 degrees Fahrenheit, which is roughly 26 to 28 degrees Celsius. The conversion is simple: Celsius equals Fahrenheit minus 32, multiplied by 5, then divided by 9. Going the other way, Fahrenheit equals Celsius times 9, divided by 5, plus 32. Temperature matters beyond comfort. Warm water burns through chlorine faster and lets algae bloom quickly, so a pool running in the mid 80s needs closer attention and often a higher free-chlorine target than the same pool in spring. Knowing the real number in the unit your heater displays helps you plan run time and dosing.
Weight Versus Liquid: Measure the Right Way
Dry and liquid pool chemicals are measured differently, and mixing the two up is a common beginner mistake. Granular products like cal-hypo, dichlor, soda ash, and baking soda are dosed by weight, so you work in ounces, pounds, or grams. A pound is 16 ounces or about 453.6 grams. Pourable products like muriatic acid and liquid chlorine (sodium hypochlorite) are dosed by volume, so you work in fluid ounces, cups, or milliliters. A fluid ounce is about 29.57 milliliters, and a US cup is 8 fluid ounces. Do not assume a fluid ounce of liquid weighs one ounce, since densities differ. Use the weight converter for anything you scoop and the liquid converter for anything you pour.
Length and Area for Sizing Gear
Length and area conversions come up when you measure your pool or shop for a cover, liner, or solar blanket sold in metric. One foot is 0.3048 meters, and one square foot is 0.092903 square meters. Measure your pool dimensions in feet to feed the US volume formulas, which use 7.48 gallons per cubic foot, then convert to meters only if a product listing or installer needs it. Surface area, your length times width, is what cover and blanket makers usually ask for, so having both units handy makes ordering painless.
A Note on ppm and Safe Dosing
The one unit you do not convert is ppm. Parts per million is how chlorine, alkalinity, calcium hardness, cyanuric acid, and salt are measured, and for pool water 1 ppm equals 1 milligram per liter. That is why pool chemistry works cleanly in metric and why the volume conversion above is the real work. Whatever units you land on, dose carefully. Never mix pool chemicals, especially different chlorine types or chlorine and acid. Always add chemical to water, not water to chemical. Run the pump while dosing, and retest your water before adding more. These figures are estimates based on standard conversion factors, so test your own water and follow every product label.
Put your converted numbers to work:
Frequently Asked Questions
What is the difference between US gallons and UK gallons?
They are not the same, and mixing them up will throw off every dose. A US gallon is about 3.785 liters, while a UK (imperial) gallon is about 4.546 liters, so a UK gallon is roughly 20 percent larger. Almost all pool dosing guidance written for the United States assumes US gallons, including every calculator on this site. If you are in the UK, Canada, Australia, or anywhere that uses imperial gallons, convert your volume to US gallons first, or better yet work in liters, before you trust a US chemical chart.
What does ppm mean in pool water and how does it relate to mg/L?
Ppm stands for parts per million, the standard unit for chlorine, alkalinity, calcium hardness, cyanuric acid, and salt in your water. For practical pool purposes, 1 ppm equals 1 milligram per liter (mg/L), because a liter of water weighs almost exactly 1,000 grams. So a test strip reading 3 ppm free chlorine is the same as 3 mg/L. This is why pool math works cleanly in metric, and why you do not need to convert ppm itself, just the volume it is dosed into.
How do I convert a chemical dose from one pool size to another?
Chemical doses scale directly with volume. If a label or chart gives an amount per 10,000 gallons and your pool is 20,000 gallons, you double it. To convert, divide your pool volume by the reference volume to get a multiplier, then multiply the listed dose by that multiplier. Use the weight and liquid converters here to switch between ounces, pounds, grams, and milliliters once you know the amount. Always round conservatively, add a little less than you think, run the pump, and retest before adding more.
Should I set my pool temperature in Fahrenheit or Celsius?
Use whichever your thermometer and heater display, then convert when you read advice from elsewhere. Most US pool guidance uses Fahrenheit, where comfortable swimming is roughly 78 to 82 F. The same range in Celsius is about 26 to 28 C. To convert, Celsius equals Fahrenheit minus 32, times 5, divided by 9. Temperature also matters for chemistry, since warm water speeds chlorine loss and algae growth, so knowing the real number in your preferred unit helps you plan dosing and run time.
Why does pool volume matter so much for converting and dosing?
Every chemical reading is a concentration, so the amount you add depends entirely on how much water you are treating. The same scoop of shock that perfectly clears a 10,000-gallon pool barely moves a 30,000-gallon pool. Getting your volume right once, in US gallons, means every future dose converts cleanly. If you are not sure of your gallons, use our pool volume calculator first, write the number down, and reuse it for chlorine, salt, stabilizer, and alkalinity math.
How do I measure dry chemicals versus liquid chemicals correctly?
Dry chemicals like cal-hypo, dichlor, soda ash, and baking soda are measured by weight (ounces, pounds, or grams), while liquids like muriatic acid and liquid chlorine are measured by volume (fluid ounces, cups, or milliliters). Do not assume a fluid ounce of liquid weighs an ounce, since their densities differ. Use the weight converter for granular products and the liquid converter for pourable ones. Always follow the product label, never mix chemicals, add chemical to water rather than water to chemical, and retest before re-dosing.