How this calculation works
Standardise a value using a known mean and standard deviation. The result is calculated locally in your browser from the visible inputs, and the method below remains available for checking.
Z = (observed value − mean) ÷ standard deviation.
Worked example
A value of 85 in a distribution with mean 70 and deviation 10 has z = 1.5.
Assumptions and limits
- Inputs use the units shown beside each field.
- Intermediate values retain precision; displayed values are rounded for readability.
Questions people ask
How does the Z-Score Calculator work?
It applies this displayed method: Z = (observed value − mean) ÷ standard deviation. Values stay in your browser and are not submitted to a server.
What should I check before using the Z-score result?
Inputs use the units shown beside each field. Intermediate values retain precision; displayed values are rounded for readability. The result follows the displayed mathematical definition and the precision of the values entered.
Does this Z-score calculator save my information?
No. Calculation inputs are processed on this device. Sharing creates a URL only when you choose the share action.