LOG DAX Function (Math and Trig)

Syntax  |  Return values  |  Remarks  |  Examples  |  Related  

Returns the logarithm of a number to the base you specify.

Syntax

LOG ( <Number> [, <Base>] )

Parameter	Attributes	Description
Number		The positive number for which you want the logarithm.
Base	Optional	The base of the logarithm; if omitted, 10.

Return values

Scalar A single decimal value.

Logarithm of number to the base specified.

Remarks

The function LOG10 is similar, but always returns the logarithm for the base 10.

» 3 related functions

Examples

--  Logarithmic functions include LOG10, LN, LOG, and EXP to compute
--  logarithms using various bases or exponential.
DEFINE
    VAR Vals = GENERATESERIES ( 1, 25, 4 )
EVALUATE
ADDCOLUMNS ( 
    Vals,
    "LN",       LN      ( [Value] ),
    "LOG10",    LOG10   ( [Value] ),
    "LOG 5",    LOG     ( [Value], 5 ),
    "EXP",      EXP     ( [Value] )
)

Value	LN	LOG10	LOG 5	EXP
1	0.00	0.00	0.00	2.72
5	1.61	0.70	1.00	148.41
9	2.20	0.95	1.37	8,103.08
13	2.56	1.11	1.59	442,413.39
17	2.83	1.23	1.76	24,154,952.75
21	3.04	1.32	1.89	1,318,815,734.48
25	3.22	1.40	2.00	72,004,899,337.39

Related functions

Other related functions are:

• LOG10
• EXP
• LN

Last update: Nov 5, 2025   » Contribute   » Show contributors

Contributors: Alberto Ferrari, Marco Russo, Kenneth Barber,

Microsoft documentation: https://docs.microsoft.com/en-us/dax/log-function-dax