Statistical
Z-Score Calculator
Standard score & percentile
Calculate the z-score of any data point with percentile ranking — the standard way to compare values across datasets.
Data Point
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How It Works
z = (x − μ) ÷ σ
x = value · μ = mean · σ = std deviation
x=85 · mean 70 · σ 10
- 1z = (85 − 70) ÷ 10
- 2z = 1.5 → ~93.3rd percentile
Result: z = 1.5 (top ~6.7%)
Pro Tip
|z| > 2 is unusual; |z| > 3 is a strong outlier signal.
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Frequently Asked Questions
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