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LOG10 Function
Summary
The Excel LOG10 function calculates the base-10 logarithm of a positive number. It returns the exponent to which 10 must be raised to produce the specified number, making it essential for logarithmic calculations in scientific, financial, and engineering analysis.
Syntax
LOG10(number)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | Number |
Yes | The positive real number (>0) for which you want the base-10 logarithm |
Using the LOG10 Function
LOG10 is widely used in mathematics, engineering, and data analysis for converting multiplicative relationships to additive ones. Common applications include pH calculations, Richter scale measurements, decibel levels, and data compression analysis.
Common LOG10 Examples
Basic LOG10 Calculation
=LOG10(86)Returns 1.9345 - the power to which 10 must be raised to equal 86.
Logarithm of 10
=LOG10(10)Returns 1 since 10¹ = 10.
Large Number Logarithm
=LOG10(100000)Returns 5 since 10⁵ = 100,000.
Power Expression
=LOG10(10^5)Returns 5, demonstrating LOG10(10^x) = x.
Frequently Asked Questions
Common Errors and Solutions
#NUM! Error
Cause: Number argument is negative, zero, or non-numeric
Solution: Ensure the number is positive (>0). Use ABS() if needed but verify mathematical validity.
#VALUE! Error
Cause: Non-numeric input
Solution: Verify cell contains a valid number, not text.
Notes
- LOG10(10) = 1 and LOG10(100) = 2 by definition
- Use LOG10 for decibel calculations: dB = 10 * LOG10(signal/reference)
- Perfect for pH calculations: pH = -LOG10([H+])
- Combine with POWER: POWER(10, LOG10(number)) = number (within floating-point precision)
- Available in all Excel versions
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in:
Content last reviewed: December 11, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+