LOG10 function
LOG10 returns the base-10 logarithm of a number: how many times 10 is multiplied to reach it. It measures orders of magnitude, counts digits, and underlies scales such as decibels and pH.
- Available in
- Every current version
- Category
- Math functions
- Returns
- The base-10 logarithm.
- Google Sheets
- Works the same in Google Sheets.
Syntax
=LOG10(number)
| Argument | Required? | What it is |
|---|---|---|
number | Required | A positive number. |
Examples
Each result below is calculated from the sample sheet by our formula engine, the same one that grades the practice.
| Cell | Formula | Result | What it shows |
|---|---|---|---|
| D2 | =LOG10(B2) | 3 | 1,000 is 10 to the 3rd: 3 |
| D3 | =LOG10(B3) | -2 | Numbers below 1 give negative logs: -2 |
| D4 | =INT(LOG10(B4))+1 | 5 | Counts the digits in a whole number: 5 |
Try it live
This is the sample sheet. Change any number or text, or edit a formula, and the results update.
Show the sample data as a table
| Input | Value | ||
| Revenue | 1000 | 3 | |
| Concentration | 0.01 | -2 | |
| Customer ID | 54321 | 5 |
Practice LOG10
Graded instantly, then re-checked on changed data.
Amplifier gain in decibels
In
D2, use LOG10 to calculate each amplifier's gain in decibels: 10 × the base-10 log of output power ÷ input power. Fill down to D6.Common mistakes
| What you see | Why, and how to fix it |
|---|---|
| #NUM! | The number is zero or negative. Check for blanks and negative values first. |
| Needed another base | LOG10 is fixed at base 10. Use LOG(number, base) for any other base, or LN for base e. |
Tips
- Undo LOG10 with a power of 10: =10^A2.
- Decibels from a power ratio: =10*LOG10(Output/Input).
Questions
Is LOG10 the same as LOG in Excel?
Yes, when LOG has no base argument: =LOG(A2) and =LOG10(A2) both use base 10.
How do I reverse LOG10?
Raise 10 to the result: =10^A2.
Last reviewed October 2026. Every example result on this page is calculated live by the Spreadsheet Practice formula engine.