SkimmerSkimmer
Free tool

Rate my pool.

Type in your latest test numbers and get an instant letter grade, a score out of 100, and a plain list of what to fix, each linked to the calculator that does the math.

How to use this calculator
  1. 1
    Test your water

    Get current readings for free chlorine, pH, total alkalinity, calcium hardness, and cyanuric acid (plus salt for a saltwater pool).

  2. 2
    Enter your numbers

    Type each reading in. Leave any field blank to skip it; the score adjusts to what you provide.

  3. 3
    Read your grade

    You get a letter grade, a score out of 100, and a green/amber/red status for each parameter. Free chlorine is graded against your CYA, not a fixed target.

  4. 4
    Fix what's flagged

    Each issue links straight to the calculator that works out the dose. Adjust, re-test, and re-score.

Want the ideal ranges on paper? Print the ideal pool chemistry cheat sheet, or track every reading over time in Skimmer.

Frequently asked

Questions about the score

How is the Pool Health Score calculated?
Each parameter you enter is graded good, borderline, or out of range against standard published target ranges, then combined into a 0–100 score and an A–F grade. Free chlorine is scored relative to your cyanuric acid level (the minimum effective chlorine is roughly 7.5% of CYA), because a single fixed chlorine target is wrong for a stabilized pool. See our methodology for the full detail.
Do I need to enter every number?
No. Leave any field blank and it's skipped; the score is calculated from whatever you provide. Entering more parameters gives a more complete grade.
Is a good score a guarantee my water is safe?
No. This is a diagnostic estimate from the numbers you type. It can't catch a bad test reading, a sanitizer problem it wasn't given data for, or anything outside the parameters entered. It doesn't replace a full test or professional judgment.
Can I share my result?
Yes. Your entries are encoded into a shareable link, so you can send your exact score to someone or save it. Nothing is stored on a server, the link carries the numbers.