Log-Normal Distribution Calculator

The mean of the natural logarithm of X — not the mean of X itself. The median of X equals e^μ.

If you have data, take the logs of your values and enter their mean here.

The standard deviation of ln(X). A larger σ makes the distribution more strongly right-skewed, with a heavier upper tail.

The (positive) value to evaluate — e.g. an income or a file size. The tool reports the probability of falling below or above it.

A cumulative probability between 0 and 1; the tool returns the value x below which a share p of the distribution lies.