Math & Trig
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=LOG()
Returns the logarithm of a number to the base you specify.
Applies To:
Excel for Microsoft 365Excel for Microsoft 365 for MacExcel 2024Excel 2024 for MacExcel 2021Excel 2021 for MacExcel 2019Excel 2016
=LOG(number, [base])
Hover argument names in the table for details.
Output typeNumber
Popularity15 / 100
VolatileNo
Dynamic ArrayNo
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◧ Arguments
| Argument | Type | Required | Description |
|---|---|---|---|
number |
Number | Required | The positive real number for which you want the logarithm. |
base |
Number | Optional | The base of the logarithm. If base is omitted, it is assumed to be 10. |
▣ Examples
Logarithm of 10. Because the second argument (base) is omitted, it's assumed to be 10. The result, 1, is the power to which the base must be raised to equal 10.
=LOG(10)
Result:
1
Logarithm of 8 with base 2. The result, 3, is the power to which the base must be raised to equal 8.
=LOG(8, 2)
Result:
3
Logarithm of 86 with base e (approximately 2.718). The result, 4.454, is the power to which the base must be raised to equal 86.
=LOG(86, 2.7182818)
Result:
4.4543473
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