What is the syntax for LN in Excel?

The syntax for LN is: =LN(number)

What are common errors with LN?

#NUM! if number is zero or negative

What is the difference between LN and LOG in Excel?

LN is the natural logarithm (base e ≈ 2.718). LOG defaults to base 10 but accepts any base as second argument. LN(x) is equivalent to LOG(x, EXP(1)). Use LN for continuous growth calculations, LOG10 for orders of magnitude.

How do I calculate growth rate using LN?

To find the continuous growth rate between two values: =LN(end_value/start_value)/periods. For example, if sales grew from 100 to 150 over 3 years: =LN(150/100)/3 = 13.5% continuous annual growth rate.

Why does LN return #NUM! error?

LN only works with positive numbers. LN(0) and LN(negative) are mathematically undefined, returning #NUM!. If your data might contain zeros or negatives, use =IF(A1>0, LN(A1), "N/A") or =IFERROR(LN(A1), "").

Math & Trig

LN Function in Excel

Returns the natural logarithm (base e) of a number.

Syntax

=LN(number)

Arguments

number (required): Positive number to find natural log of

Examples

=LN(2.718) - Natural log of e - Result: ~1
=LN(10) - Natural log of 10 - Result: 2.302...

LN in reporting workflows

Use absolute references when copying formulas across rows.
For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.

Common errors

#NUM! if number is zero or negative

Use cases

Growth rate calculations
Scientific analysis
Inverse of EXP

Frequently asked questions

What is the difference between LN and LOG in Excel? LN is the natural logarithm (base e ≈ 2.718). LOG defaults to base 10 but accepts any base as second argument. LN(x) is equivalent to LOG(x, EXP(1)). Use LN for continuous growth calculations, LOG10 for orders of magnitude.
How do I calculate growth rate using LN? To find the continuous growth rate between two values: =LN(end_value/start_value)/periods. For example, if sales grew from 100 to 150 over 3 years: =LN(150/100)/3 = 13.5% continuous annual growth rate.
Why does LN return #NUM! error? LN only works with positive numbers. LN(0) and LN(negative) are mathematically undefined, returning #NUM!. If your data might contain zeros or negatives, use =IF(A1>0, LN(A1), "N/A") or =IFERROR(LN(A1), "").

Editorial review

Reviewed by Excel.Directory Editorial Team. Updated May 2026.