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Z-Score Calculator — Free Online Calculator

Calculates the z-score and percentile for a value in a normal distribution.

What is it?

The z-score calculator shows how many standard deviations a value lies from the mean and finds its percentile.

Formula

z = (x − x̄) / σ Percentile = Φ(z) × 100%, from the standard normal distribution.

Example

Height 175 cm, mean 170 cm, σ = 10 cm. z = (175 − 170) / 10 = 0.5. Percentile ≈ 69.2% (taller than about 69% of people).

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