Z-Score Calculator
Express a measurement as standard deviations from the mean.
Your inputs
Calculation results
Formula & assumptions
z = (x−μ)/σ; this does not determine a percentile without a distribution assumption.
Values use the specified units. Calculations use floating-point arithmetic. Check input measurements and formula assumptions before applying the result.
Compare your scenarios
Save up to five results to compare changes side by side. Scenarios stay in this tab until you clear or reload it.
Using Z-Score Calculator
Express a measurement as standard deviations from the mean.
- Enter measurement, mean, standard deviation using the units printed under each field.
- Choose Calculate, or enable live updates. Review the result labels and formula assumptions.
- Save scenarios to compare up to five variations, then copy the report or download JSON or CSV.
Example
Measurement: 85 units Mean: 70 units Standard deviation: 10 units Z score: 1.5 Difference from mean: 15
Questions & answers
What does Z-Score Calculator calculate?
Express a measurement as standard deviations from the mean.
Which units should I enter?
Measurement uses units. Mean uses units. Standard deviation uses units. Convert values to these units before calculating.
Which formula does it use?
z = (x−μ)/σ; this does not determine a percentile without a distribution assumption.
What does the included example show?
Measurement: 85 units; Mean: 70 units; Standard deviation: 10 units. Result: Z score = 1.5; Difference from mean = 15.
Can I compare different settings?
Yes. Save a scenario, change the inputs and save another result. Up to five scenarios are compared in this tab; they disappear when you reload or leave.
Can I export the calculation?
Copy the JSON report or download JSON and CSV with inputs, result labels and numeric values. Processing uses local JavaScript; no calculation request is sent to our server. Displayed values use up to 10 significant digits; exports retain JavaScript numeric precision.
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