Free Z-Score & Normal Distribution Probability Calculator Online
Calculate Z-scores (standard score z = (x - μ) / σ), percentile ranks, and cumulative normal distribution probability P(Z < z). — 100% free online utility, zero sign-up, zero paywalls, and private client-side processing.
How It Works
Enter Raw Score (x)
Input individual test score or measurement value.
Enter Population Mean (μ)
Input expected average benchmark.
Enter Standard Deviation (σ)
Input population or sample standard deviation.
Inspect Z & Percentile
Review Z-score, left-tail P(X < x), and right-tail probabilities.
Frequently Asked Questions
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