Log-Normal Distribution in Google Sheets
For anything that can't go below zero — prices, durations, deal sizes.
Interactive Sandbox
10,000 simulations running live in your browser.
When to use it
The Log-Normal distribution is what you reach for when values must be strictly positive and you expect a long right tail: project costs almost always run over, never under zero. Salaries, asset prices, and time-to-failure all follow this shape. Parameterized by the mean and standard deviation of the underlying log-transformed variable, it's the workhorse of financial risk modeling.
- Project cost estimation with no chance of negative spend
- Startup revenue projections with high upside potential
- Insurance claim size modeling
- Time-to-failure analysis in reliability engineering
How to build it
Native Sheets Formula
=LOGNORM.INV(RAND(), logMean, logStdev) Using native RAND() requires you to copy this formula 10,000 times manually, which severely lags the browser.
The MonteSheet Way
MonteSheet uses a local browser engine to run 100,000 iterations in 4 seconds without writing a single formula.
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