LN Function
Returns the natural (base-e) logarithm of a number.
Syntax
Parameters
| Parameter | Description | Required |
|---|---|---|
| number | The positive real number for which you want the natural logarithm. | Required |
Basic Example
Natural log of 1
=LN(1)e⁰ = 1, so the natural logarithm of 1 is 0.
Advanced Examples
Example 1: Cancel with EXP
Verify the inverse relationship.LN(EXP(x)) returns x.
=LN(EXP(3))Example 2: Natural log of e
Baseline check.Use EXP(1) as the argument.
=LN(EXP(1))How LN Works
LN computes logₑ(number), the power to which e must be raised to equal the input. It is the inverse of EXP: LN(EXP(x)) = x for all real x, and EXP(LN(x)) = x for x > 0.
Important Notes & Limitations
The argument must be strictly positive; zero or negative values return #NUM!.
Results are floating-point approximations.
For other bases use LOG(number, base) or divide by LN(base).
Common Errors & Fixes
#NUM!Argument is 0 or negative.Fix: Pass a positive number; the natural log of non-positive values is undefined.
#VALUE!Non-numeric argument.Fix: Supply a numeric value.
Download Practice File
LN
lnPractice LN with Real Data
Download a sample CSV file with pre-populated data and practice exercises for the LN function. Works in both Excel and Google Sheets.
File format: CSV (comma-separated values) - opens in Excel, Google Sheets, and all spreadsheet apps