LN function

LN returns the natural logarithm of a positive number, useful for growth rate analysis, logarithmic scaling, and financial calculations.

=LN(number)

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  • Name your columns by letter and by header: "column F (Net Value)" beats "the amount column".
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Arguments

How LN reads its arguments
numberrequiredLN →
ArgumentRequiredDescription
numberRequiredA positive real number; must be greater than 0. Passing zero, negative numbers, or text produces an error.

Returns

Returns a decimal number representing the natural logarithm (base e ≈ 2.718) of the input.

Availability

Excel: All · Google Sheets: Supported

Worked examples

1. Calculate price appreciation rate between properties

AddressOriginal PriceCurrent Price
42 Oak St350000485000
=LN(485000/350000)

Result: 0.3211

LN returns the natural logarithm of the price ratio (1.3857), which equals 0.3211. This represents the logarithmic growth rate. Financial analysts use this to standardize growth across different price ranges, since a $135k increase on a $350k property represents the same proportional growth as a $135k increase on a $485k purchase when measured logarithmically.

2. Convert list prices to logarithmic scale for chart visualization

AddressList PriceLog Price
42 Oak St35000012.7664
18 Maple Ave48500013.0919
99 Birch Dr27500012.5244
=LN(350000)

Result: 12.7664

LN(350000) returns 12.7664. Converting prices to log scale compresses the range of large numbers (275k to 625k becomes 12.52 to 13.34), making it easier to visualize proportional differences on a chart. Properties that differ by hundreds of thousands appear in a compressed range, revealing percentage-based patterns more clearly than linear scale.

3. Analyze market velocity using logarithmic decay of days on market

AddressDays on MarketMarket Velocity
99 Birch Dr323.4965
42 Oak St152.7726
18 Maple Ave82.1972
=LN(32+1)

Result: 3.4965

LN(32+1) returns 3.4965 (we add 1 to avoid LN(0)). The logarithmic scale shows that a property lasting 32 days is significantly slower than one lasting 8 days. The log values (3.50 vs 2.20) reveal that market velocity follows a diminishing curve: each additional day on market has less proportional impact when the listing is already old.

Common errors

Which LN error are you seeing?
LN returned an error#NUM!
Ensure the input is a positive number greater than 0. If processing days on market where 0 is possible, add 1: =LN(days+1). To handle negative numbers, use ABS: =LN(ABS(number)).
#VALUE!
Verify the cell reference points to numeric data only. Wrap the formula in IFERROR to catch misaligned references: =IFERROR(LN(price), "Check data"). Ensure no leading or trailing spaces in number cells.
#NAME?
Check the spelling: type =LN(number) exactly with no extra spaces. In non-English Excel versions, use the localized function name provided in the Function Wizard dropdown.
ErrorWhy it happensHow to fix it
#NUM!LN requires a positive number. Passing zero, negative numbers, or numbers less than or equal to 0 produces this error because the natural logarithm is mathematically undefined for non-positive values.Ensure the input is a positive number greater than 0. If processing days on market where 0 is possible, add 1: =LN(days+1). To handle negative numbers, use ABS: =LN(ABS(number)).
#VALUE!If the input is text that cannot be converted to a number, LN returns #VALUE!. This happens when you reference a cell containing text like a property address or accidentally include a non-numeric column in your formula.Verify the cell reference points to numeric data only. Wrap the formula in IFERROR to catch misaligned references: =IFERROR(LN(price), "Check data"). Ensure no leading or trailing spaces in number cells.
#NAME?Excel does not recognize the function name, usually due to misspelling or extra spaces (e.g., =LN ( ) with space before parenthesis, or using a regional variant where the function name differs).Check the spelling: type =LN(number) exactly with no extra spaces. In non-English Excel versions, use the localized function name provided in the Function Wizard dropdown.

Tips and when to use something else

  • For logarithm base 10 or a custom base, reach for LOG instead—a different function that handles base-10 and arbitrary-base logarithms.
  • LN results are often irrational decimals; use ROUND to control precision: =ROUND(LN(price), 4) returns a more readable value for reports.
  • To work with multiple growth factors, combine LN with PRODUCT: log-transforming several values, summing them, then applying PRODUCT on the original values models compound growth.
  • When combining LN with conditional logic, use IFERROR to prevent cascading errors: =IFERROR(LN(value), 0) safely handles edge cases where value might be zero or negative.

Related functions

ROUNDROUND returns a number rounded to a specified number of decimal places, using standard rounding rules (0.5 rounds up).PRODUCTReturns the product of all numeric values supplied as arguments, multiplying them together into a single result.IFERRORIFERROR returns the result of a formula unless that formula generates an error, in which case it returns a user-specified alternative value.ABSABS returns the absolute value of any number, removing the sign to show only magnitude, useful for comparing distances regardless of direction.

Frequently asked questions

What does LN mean, and why is it called 'natural'?
LN is the natural logarithm, the inverse of exponential growth with base e (≈2.71828). It's called 'natural' because e emerges naturally in calculus, compound interest, and exponential decay models. In finance and science, e is more fundamental than 10, making LN more natural than base-10 logarithms for modeling real-world growth.
Why would I use LN instead of just dividing numbers?
LN converts multiplicative relationships (ratios) into additive ones, which is crucial for analysis. A property that doubles in price (×2) and one that triples (×3) appear different in raw numbers, but their log returns (LN(2)≈0.693, LN(3)≈1.099) reveal proportional growth on a comparable scale. This is essential for comparing markets with very different price ranges.
Can LN handle negative numbers or zero?
No. LN of zero or negative numbers produces #NUM! error. Mathematically, the natural logarithm is undefined for non-positive values. If your data might include zero or negative values, use IFERROR to skip them, add a small offset like =LN(value+0.01), or use ABS to work with absolute values.
How accurate is LN for very large property prices?
LN is accurate across the entire range of positive numbers, from small decimals to very large values. For a $10M property, LN(10000000) ≈ 16.118. The precision depends on your system's floating-point arithmetic (typically 15 significant digits). For real estate analysis, ROUND the result to 2–4 decimal places for readability without sacrificing accuracy.

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Reviewed 2026-09-17