Z-Score: IQ Score 100, Mean 100, SD 15
An IQ score of 100 with mean 100 and SD 15 yields a z-score of 0.0, exactly at the population average.
How to use this tool
- Enter data point (x), mean (μ) and standard deviation (σ) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your z-score and the full breakdown beneath it.
Calculate the z-score for an IQ of 100, which sits exactly at the mean of the standard IQ distribution (μ = 100, σ = 15).
Frequently asked questions
- What does a z-score mean?
- A z-score of +1 means the value is 1 standard deviation above the mean; −2 means 2 standard deviations below. Z-scores allow comparison across different scales and distributions.