📊 Z-Score Calculator
Calculate z-scores and probabilities
How Z-Score Calculation Works
- 1Enter the raw value (x), population mean (μ), and standard deviation (σ).
- 2Z = (x − μ) / σ is computed.
- 3The corresponding percentile and probability from the standard normal table are displayed.
About Z-Score Calculator
Calculate the z-score (standard score) from a raw value, mean, and standard deviation. Also find probabilities from z-tables.
Frequently Asked Questions
What does a z-score tell me?
It tells you how many standard deviations a value is from the mean. A z-score of 2 means the value is 2 SDs above the mean.
What z-score is statistically significant?
Typically |z| ≥ 1.96 corresponds to p < 0.05 (95% confidence), which is the common significance threshold.