Z-Score Calculator

Your details

Choose what you want to find. Switch modes to reverse-solve or get area between two z-scores.
The individual observation you want to standardize.
Population mean (or sample mean if you only have sample data).
Must be greater than zero. Use population SD (sigma) or sample SD (s) consistently with your mean.
Z-scoreBetween 1 and 2 SDs
1.5

Standard deviations from the mean.

Raw value (x)85
P(X <= x) -- left tail93.319%
P(X > x) -- right tail6.681%
P(|X| > |z|) -- two-tailed13.361%
P(-|z| < X < |z|) -- middle area86.639%
Percentile rank93.32%
1.5 SD93.3% below · standard normal distribution

Z = 1.5000, at the 93.3th percentile.

  • The value is 1.50 standard deviations above the mean.
  • Left tail: 93.32% of the distribution falls at or below this score.
  • Two-tailed: 13.36% of values are this far or farther from the mean in either direction.
  • The 68-95-99.7 rule: ~68% of data falls within z = -1 to 1, ~95% within -2 to 2, ~99.7% within -3 to 3.

Next stepMost values in a normal distribution fall within |z| = 2. This score is fairly typical.

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