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Normal distribution probability Calculator

Free normal distribution probability calculator to calculate normal distribution probability. Instant results in your browser — no signup.

Also known as: Calculate normal distribution probability, normal distribution calculator, normal CDF, bell curve probability, gaussian calculator, calculate normal distribution probability calculator, calculate normal distribution probability, probability math

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Inputs

Input mode

Results update when you click Calculate.

P(Z ≤ z)

97.50%

z = 1.9600 → cumulative area ≈ 97.50%

P(Z > z)

2.50%

Z-score used

1.9600

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What this result means

Free normal distribution probability calculator to calculate normal distribution probability. Instant results in your browser — no signup. Uses the standard normal CDF approximation for P(Z ≤ z).

Assumptions

  • Rule dependency: Universal formula.

How is it calculated?

Uses the standard normal CDF approximation for P(Z ≤ z).

Example

z = 1.96 → about 97.5% below (one-tailed).

Frequently asked questions

Two-tailed?+

Double the upper-tail probability for symmetric two-tailed tests.