The pool stabilizer calculator gives you a practical estimate of how much cyanuric acid may be needed for a selected CYA target. Use the pool stabilizer calculator when CYA is too high as well, so you can see an estimated water-replacement amount before making a change.
Free interactive calculatorWater Chemistry
CYA
FREE ONLINE CALCULATOR
Cyanuric Acid (CYA) / Stabilizer Calculator
Estimate stabilizer to add when CYA is low, or estimate water replacement when CYA is too high.
CYA
YOUR ESTIMATE
Estimated stabilizer adjustment
Planning estimate
Stabilizer needed——
Metric amount——
CYA change——
Containers——
Important: Cyanuric acid is a pool chemical. Use the exact product label, avoid over-correction, allow the water to circulate and retest before making another adjustment. For a high CYA reading, a drain-and-refill estimate assumes the replacement water has little or no CYA and that the pool is well mixed.
ABOUT THIS TOOL
What this calculator helps with
Water Chemistry
The pool stabilizer calculator gives you a simple way to estimate how much cyanuric acid may be needed to move a measured pool CYA level toward a target. The pool stabilizer calculator can also estimate how much water may need to be replaced when the CYA level is higher than the level you want.
Why this calculation matters
Cyanuric acid, often called pool stabilizer or conditioner, helps reduce chlorine loss from sunlight. A useful estimate starts with the pool volume and a current CYA test, then compares that reading with the target for the pool and chlorine system. The result is meant for planning and should be checked against the product label, test method and equipment guidance.
Details to have ready
Pool water volume and the unit you use.
Current CYA reading from a recent, suitable pool-water test.
Target CYA level for your chlorine system or the custom target you choose.
Stabilizer product purity or active-ingredient percentage when estimating an addition.
For CYA reduction, the amount of replacement water assumed to have little or no CYA.
How to prepare
Enter the pool volume and select US gallons or litres.
Enter the current CYA reading from your latest test.
Choose your chlorine system to load a starting target, then adjust the target when your product or equipment guidance calls for a different level.
Choose Add stabilizer to estimate product needed, or Lower CYA to estimate water replacement when the reading is too high.
Use the result as a planning estimate, follow the product label and retest the water after circulation.
Note: CYA targets vary by pool, chlorine system, manufacturer guidance and local rules. This tool uses 40 ppm as a practical starting target inside a commonly referenced 30–50 ppm range, but the product label and applicable guidance should take priority.
CALCULATION GUIDE
COMMON QUESTIONS
About Cyanuric Acid (CYA) / Stabilizer Calculator
What is a pool stabilizer calculator?
A pool stabilizer calculator estimates the amount of cyanuric acid needed to move a measured CYA level toward a target. It can also estimate water replacement when CYA is too high.
What CYA target should I use for my pool?
A common starting reference for many residential pools is 30–50 ppm. This calculator starts at 40 ppm and lets you change the target when your chlorine system, equipment manual or local requirements call for something different.
How much stabilizer do I add to a pool?
The amount depends mainly on pool volume, the difference between current and target CYA and the purity of the stabilizer product. Use the pool stabilizer calculator result as a planning number and check the product label before adding it.
Is this a cyanuric acid calculator or CYA calculator?
Yes. Cyanuric acid calculator, CYA calculator, pool CYA calculator and pool stabilizer calculator all describe the same general planning task when adjusting cyanuric acid in pool water.
How do I lower CYA in a pool?
CYA does not normally leave through evaporation. A partial drain and refill can reduce CYA when the replacement water has little or no CYA. The calculator estimates the replacement percentage from the current and target readings.
Does chlorine type change the CYA target?
The chlorine system matters when choosing a target, but there is not one universal target for every pool. The calculator provides a 40 ppm starting point inside a commonly referenced 30–50 ppm range and lets you change it to match your equipment or local guidance.
Can I use a pool stabilizer calculator in litres?
Yes. Enter the volume in litres and the calculator converts it to US gallons for the dose estimate, while also showing the metric amount in the result.
What is chlorine stabilizer?
Chlorine stabilizer is another common name for cyanuric acid (CYA). It helps reduce chlorine loss from sunlight, but free chlorine and pH still need regular testing.
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