LN Function in Google Sheets: Examples, Pitfalls & Compatibility

=LN(value)

value (required): A strictly positive real number. Zero and negative values are outside this real-valued domain.

Examples use English function names, comma argument separators and decimal points. Adapt formula separators to your workbook settings, not punctuation inside quoted text.

Use LN to solve for an exponent in an e-based model or to transform a positive ratio. Use LOG10 or LOG when another base is specified. A negative logarithm can be valid even though a negative logarithm input is not.

Each example is independent. Where input cells are listed, enter those values first; otherwise the formula is self-contained. Expected outputs are independently checked calculations or documented error expectations, not captured results from Google Sheets.

Example 1: Transform a positive ratio below one

=ROUND(LN(0.5),6)

Expected result: -0.693147.

The input is positive and valid; the negative output represents a factor smaller than one.

Example 2: Check an inverse pair

=ROUND(LN(EXP(4)),6)

Expected result: 4.

The mathematical inverse produces the expected value after the stated rounding.

Example 3: Solve a doubling-time model

=ROUND(LN(2)/0.15,6)

Expected result: 4.620981.

In the assumed model EXP(0.15*t)=2, taking natural logs gives t=LN(2)/0.15. Time uses the unit paired with the rate.

Validate the input before the transform and keep the untransformed value beside it. A ratio below one but above zero has a negative natural logarithm, which is not an error. Do not apply ABS or add an arbitrary constant simply to suppress invalid inputs: either transformation changes the model and needs its own justification.

A positive fraction produces a negative answer. That is expected for inputs between zero and one. Do not confuse the sign of the output with the allowed input domain.

Zero is included in the source data. LN is not defined at zero in this real-valued calculation. Decide how the process should represent or exclude that observation.

A rounded value of e does not invert perfectly. Use EXP to construct an e-based value and use an appropriate tolerance rather than demanding exact equality after approximate arithmetic.

Google likewise specifies positive inputs and relates LN to LOG with base e. The examples include a positive fraction so that a negative output is not mistakenly treated as a failed calculation. See the vendor reference for the current definition.

The positive-real mathematical interpretation matches. Exact error displays, text coercion and machine precision beyond the reported examples are not certified for either application.

Compare the LN guide for Microsoft Excel and its official documentation. Having a guide in both libraries establishes two documented references, not a certificate of identical behavior across releases, locales or file conversions.

EXP, LOG, LOG10, IF · All Google Sheets functions.

Editorial verification: Official references retrieved on 2026-10-12. The three worked cases are included in this release’s reproducible Python checking suite. It checks the stated arithmetic, calendar or text model and the expected documented error classification; it is not the Google Sheets calculation engine. No native application run, UI screenshot, maximum-size benchmark or cross-version certification is claimed. Review the editorial testing standards before relying on a formula in a critical workbook.