Statistics

Z-Score Calculator

Compute the z-score of any raw value, then read off the percentile, one-tailed and two-tailed probabilities from the standard normal distribution.

Formula: z = (x − µ) ÷ σ. Scores in a normal distribution follow the 68-95-99.7 rule.
0th50th100th percentile

📊 Standard normal

Exact cumulative probabilities via the error function.

📈 Percentile bar

Visualize where your score falls among the population.

⚠ Tails included

One-tailed and two-tailed p-values ready for tests.

⚡ Instant

No tables to flip through — results appear instantly.

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From raw data to confidence.