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Z-Score & Standard Normal Score Calculator

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Calculate standard normal distribution Z-scores, cumulative probabilities P(Z ≤ z), two-tailed p-values, and percentile rankings.

Parameters
Z-Score Results
Z-Score
+1.500
Percentile
93.32%
Two-Tailed p-value: 0.1336

Helpful Examples

Test Score Standardization

Raw Score: 85, Mean: 70, Std Dev: 10 -> Z = +1.50 (93.3% Percentile)

X=85, μ=70, σ=10

How to Use the Z-Score & Standard Normal Score Calculator

Statistical Z-score and probability calculator. Standardize raw observation scores relative to population mean and standard deviation: Z = (X - μ) / σ. Computes exact cumulative area under the standard normal curve, percentile rank, and two-tailed significance p-values.

Privacy & Data Processing Notice

No user data leaves your browser. Computation is executed entirely on your device. We do not store, view, or transmit your inputs over our network. Your computation remains on your personal machine.

Frequently Asked Questions

What does a Z-score of +2.0 mean?
A Z-score of +2.0 means the raw score is exactly 2 standard deviations above the population mean, placing it in roughly the 97.7th percentile of a normal distribution.

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