Z-Score Calculator
Turn a raw score into a z-score, and find the probability below, above or between values on any normal distribution.
Updated · By Bibin XavierData 90 × 12
| IDtext · 90 levels | Grouptext · 3 levels | Gendertext · 2 levels | Agenumeric | Hours_Studynumeric | Anxietynumeric | Motivationnumeric | Pre_Scorenumeric | Post_Scorenumeric | Exam_Scorenumeric | Passednumeric · coded | Satisfactionnumeric · coded |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S001 | Control | Male | 23 | 11.2 | 29 | 4.6 | 60 | 62 | 67 | 1 | 2 |
| S002 | Workshop | Female | 23 | 3.9 | 28 | 3.5 | 54 | 70 | 54 | 0 | 2 |
| S003 | Online | Female | 18 | 10.1 | 32 | 4 | 55 | 57 | 66 | 0 | 3 |
| S004 | Control | Male | 26 | 13.6 | 41 | 3.5 | 52 | 55 | 59 | 0 | 3 |
| S005 | Workshop | Female | 22 | 9.7 | 27 | 3.6 | 56 | 63 | 65 | 0 | 4 |
| S006 | Online | Female | 20 | 7.9 | 32 | 3.8 | 65 | 82 | 65 | 0 | 2 |
| S007 | Control | Female | 20 | 6.3 | 28 | 3 | 72 | 83 | 61 | 0 | 3 |
| S008 | Workshop | Male | 22 | 8 | 29 | 3.1 | 64 | 72 | 62 | 1 | 3 |
Variables and options
Results
Calculated in your browserAreas under the curve
| Region | Probability |
|---|---|
| Below 118.00 | .8849 |
| Above 118.00 | .1151 |
| Between μ ± 1.20σ | .7699 |
| Outside μ ± 1.20σ (two-tailed p) | .2301 |
Normal curve
Interpretation
A value of 118.00 is 1.20 standard deviations above the mean. About 88.5% of the distribution falls below it.
How to cite this tool
Using these results in a thesis, journal article, report or class assignment? Please cite this free tool so others can find it. It keeps the site free.
APA 7
Xavier, B. (2026). Z-Score Calculator [Web application]. FreeStatisticalTools.com. https://freestatisticaltools.com/z-score-calculator/
BibTeX
@software{xavier_zscorecalculator_2026,
author = {Xavier, Bibin},
title = {Z-Score Calculator},
publisher = {FreeStatisticalTools.com},
year = {2026},
url = {https://freestatisticaltools.com/z-score-calculator/},
note = {Web application}
}Suggested sentence for your methods section: “The analysis was carried out with the free Z-Score Calculator tool on FreeStatisticalTools.com (Xavier, 2026).”
What is a z-score?
A z-score tells you how many standard deviations a value lies above or below the mean. Enter a value, the mean and the standard deviation to get the z-score, its percentile, and the area under the normal curve on either side.
When to use a z-score
Use z-scores to compare values measured on different scales or to locate a score within a normal distribution.
How to use this calculator
- Enter the values. Fill in value (x), mean (μ) and standard deviation (σ).
- Read the results. Results update automatically. Read the plain-English interpretation, then use Copy table to paste APA-style tables into Word and Copy for the results sentence.
Frequently asked questions
What is the z-score formula?
z = (X − μ) / σ, where X is the value, μ is the mean and σ is the standard deviation.
What z-score is the 95th percentile?
A z-score of 1.645 marks the 95th percentile of the standard normal distribution, and ±1.96 bounds the middle 95%.
Can a z-score be negative?
Yes. A negative z-score means the value is below the mean; for example z = −1 is one standard deviation below average.
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