Syntax
LOGNORMDIST(x, mean, standard_dev)
| Parameter | Description |
|---|---|
| x | Parameter of the LOGNORMDIST function. |
| mean | Parameter of the LOGNORMDIST function. |
| standard_dev | Parameter of the LOGNORMDIST function. |
Examples
Cumulative probability for asset price
Formula
=LOGNORMDIST(50, 3.5, 0.8)
Returns ~0.3735. About 37% of the distribution falls at or below x=50 given mean=3.5 and std=0.8 of the log-transformed values.
Probability of completing within time
Formula
=LOGNORMDIST(30, LN(20), 0.5)
Returns ~0.7939. If task completion times are lognormally distributed with geometric mean 20 days, there's about a 79% chance of finishing within 30 days.
Quality threshold probability
Formula
=LOGNORMDIST(100, 4, 0.6)
Returns the probability that a lognormally distributed measurement stays at or below 100.
Common Errors
#NUM!
x must be positive and standard_dev must be greater than 0.
#VALUE!
Occurs when any argument is non-numeric text.
Tips
Always returns cumulative
Unlike LOGNORM.DIST, this function has no cumulative toggle — it always returns the CDF. Use LOGNORM.DIST(x, mean, std, FALSE) if you need the PDF.
Migrate to LOGNORM.DIST
LOGNORMDIST is kept for backward compatibility. Use LOGNORM.DIST in new spreadsheets for clarity and access to the PDF option.
Check your parameters
Remember that mean and standard_dev describe the distribution of ln(x), not x itself. If your raw data has mean 100, the lognormal mean parameter should be around LN(100) = 4.6.
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