# LOG

## Content

This function returns the logarithm base Y of a number X.

## Syntax

`LOG(number, [base])`

## Arguments

This function has these arguments:

| Argument | Description |
| -------- | ----------- |
| *number* | [Required] Number for which to find a logarithm. This must be a positive real number |
| *base* | [Optional] Base of the logarithm; if omitted, the calculation uses 10 as the base (See [LOG10](/document-solutions/dot-net-excel-api/docs/online/formula-reference/math-and-trigonometric-functions/log10).) |

## Examples

`LOG(B3,C5)`
`LOG(R1C2,R4C4)`
`LOG(255,16)` gives the result 1.998588359