Calculate lognormal probabilities, density, and summary statistics from the distribution parameters.
Last updated: June 2026 | By Patchworkr Team
A lognormal distribution describes a positive random variable whose logarithm is normally distributed. It is common in finance, reliability analysis, and growth processes where values multiply rather than add.
With mu = 0, sigma = 1, and x = 2, the calculator returns the cumulative probability and related statistics.
Why must x be positive?
The lognormal distribution only exists for positive values because it is defined through ln(X).
What does sigma represent?
Sigma is the standard deviation of ln(X), not the standard deviation of X itself.
Can I ask for a between probability?
Yes. Choose the between mode and provide both x and x2 with x2 greater than x.
Does the calculator accept decimals?
Yes. Any finite real mu, sigma, and x values are accepted as long as the domain restrictions are met.
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