Returns the variance of a sample population.




Term Definition
columnName The name of an existing column using standard DAX syntax, usually fully qualified. It cannot be an expression.

Return value

A number with the variance of a sample population.



  1. VAR.S assumes that the column refers to a sample of the population. If your data represents the entire population, then compute the variance by using VAR.P.

  2. VAR.S uses the following formula:

    ∑(x - x̃)²/(n-1)

    where x̃ is the average value of x for the sample population

    and n is the population size

  3. Blank rows are filtered out from columnName and not considered in the calculations.

  4. An error is returned if columnName contains less than 2 non-blank rows.

This DAX function may return different results when used in a model that is deployed and then queried in DirectQuery mode. For more information about semantic differences in DirectQuery mode, see


The following example shows the formula for a measure that calculates the variance of the SalesAmount_USD column from the InternetSales_USD for a sample population.