Looking for help with calculations for your swimming pool or hot tub chemistry? The Pool Calculator does all the math for you, making testing and treating your pool or hot tub a breeze.

Pool Calculator tells you exactly how much of each chemical to add to keep your water in balance and crystal clear. No more puzzling over complicated charts and formulas.

Bring your iPhone or iPad out to the pool and have all the chemical information and calculations you need right at your fingertips.

Pool Calculator works offline and online, so if you have poor internet reception by your pool, you’re still able to get test results.

Pool Calculator provides a complete tool kit to make pool care easy. You get:
• Chemical Calculator
• Pool Volume Calculator
• Chemical Effects (What-if) Calculator

You can use whichever test strip or test kit you prefer for testing your pool or hot tub. Pool Calculator provides calculations for:
- Chlorine (FCl)
- Raising pH
- Lowering pH
- Total alkalinity (TA)
- Calcium hardness (CH)
- Stabilizer (CYA or cyanuric acid)
- Salt
- Borate (Borax)
- Calcium saturation index (CSI, similar to LSI)

With Pool Calculator, the recommended ranges for your chemicals are based upon whether you have a pool or hot tub, and the surface material (plaster, vinyl or fiberglass) of your pool or hot tub. You can choose from several pre-defined ranges or customize based on your or your pool pro’s preferences.

To keep your swimming pool or hot tub at its best, it’s important that you accurately calculate your water volume. All of the chemical balancing recommendations you receive from the Pool Calculator are based on it. You can calculate the volume of your pool in metric units (liters) or in imperial units (gallons). The Pool Volume Calculator can be used for:
• Rectangular Pools and Hot Tubs
• Oval Pools and Hot Tubs
• Round Pools and Hot Tubs

“What if” analysis for adding chemicals to your pool or hot tub! Ever want to know the impact of adding a given amount of Chemical has on your swimming pool or hot tub chemistry?

The Chemical Effects Calculator calculates the impact adding a specific amount of chemical has on your pool chemistry. It does this not only for the primary purpose of the chemical, but also on the other important measurements for your pool. For example, adding Trichlor not only raises your Free Chlorine, it also increases your Cyanuric Acid, lowers your pH and increases your Salt. Adding Cal Hypo raises Free Chlorine, and also raises Calcium Hardness (CH) and Salt.

With the Chemical Effects Calculator, you can measure the effects on pool chemistry of adding a given dose of:
• Bleach
• Trichlor
• Dichlor
• Cal-hypo
• Lithium Hypochlorite
• Chlorine gas
• Muriatic Acid
• Dry Acid
• Washing soda
• Soda Ash
• Borax
• Sodium Tetraborate Pentahydrate
• Boric Acid
• Caustic Acid (lye)
• Baking Soda
• Calcium Chloride
• Calcium Chloride dihydrate
• Stabilizer
• Liquid Stabilizer
• Salt

PoolCalculator can be used for in ground or above ground pools, spas and hot tubs, chlorine or salt pools, and a broad range of surfaces.

What’s New

Version 3.0.1

We've updated the app to use the native iOS selection capabilities rather than using a separate page for selections. This simplifies and improves the user experience.

We've also updated the logo and splash screen to reflect the fun we hope you have with your pool or hot tub this summer!

Ratings and Reviews

4.2 out of 5
307 Ratings

307 Ratings

FF Ranch ,

Finally crystal clear water!!

Love this app! This app coupled with the HTH 6-way test kit (liquid set - not the paper strips which expire) tells me exactly how much of what chemical to add to get my pool balanced. I struggled for months with info from the Internet until I found the pool calculator website and downloaded the app. Just plug in the results from the test kit and follow the advice from the app. Works perfectly for us. This is the best $5 I have spent all year! Thank you for helping me make our pool beautiful to swim in!

NvHunter ,

Good app but could be better

I like the app and use it everyday. It really helps keep track of my chems. The only thing I can think of to make it better would be a box to add notes for the test. E.g. I like to check my total chlorine and my phosphates. There are no fields for those. I'm sure if you put every test possible the app would not be reasonable to use but if there was a field to add a quick note, that would make it easier to keep track of other values. But it's a great app!👍

Barzdude ,

Quick calculations

Had the older app and loved it but this one is amazing. We have a service company and I have it on all of the iPads that the guys use. If they had a Spanish option that really would take it to 20 stars. The drop down lists of chemicals is also very useful. Big thumbs up.


Pool and Spa Resources, LLC
66.7 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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