Z-Score Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter a value, the mean and the standard deviation.
- Read the z-score and approximate percentile.
How it works
Z = (value − mean) ÷ standard deviation. The percentile assumes a normal distribution.
Worked example
x=85, μ=70, σ=10. Z = 1.5 (≈ 93rd percentile).
Tips
- Runs entirely in your browser. Your inputs are not saved or transmitted.
Frequently asked questions
What does a z-score mean?
How many standard deviations a value is above (+) or below (−) the mean.
Privacy?
Runs entirely in your browser. Your inputs are not saved or transmitted.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.