Question: What is the opposite of EOMONTH()? I am trying to find the beginning date of 12 months ago. Would it be EOMONTH(Current Date,12)-1?

Any direction would be great. TIA

Answer: 
In general, the opposit function is STARTOFMONTH:

```
=STARTOFMONTH('Date'[Current Date])  

```

If you want to get the first day of the month 12 months ago:

```
= STARTOFMONTH ( DATEADD ( 'Date'[Current Date], -12, MONTH ) )

```

This measure will return the first date of the same month a year ago (i.e., for 2018-09-22, it will return 2017-09-01). Current month is included, so you will get a total of 13 months. If you need only 12 months total:

```
 = STARTOFMONTH ( DATEADD ( 'Date'[Current Date], -11, MONTH ) )

```

If you are trying to compute something over a rolling 12 months period, this article should help:
[12-month Rolling Average in DAX](https://www.sqlbi.com/articles/rolling-12-months-average-in-dax/)
There is no straight opposite function for EOMONTH() in DAX. But you can still use EOMONTH() to get the first date of a month.

Last date of a month

```
= EOMONTH(Leaves[LeaveStart]

```

First date of a month

```
= EOMONTH(Leaves[LeaveStart],-1)+1

```

You can also just use 1 in place of date to get first day of a month, like:

```
= DATE(YEAR(Leaves[LeaveStart]), MONTH(Leaves[LeaveStart]), 1)

```

Please note that STARTOFMONTH() is opposite function for ENDOFMONTH() not for EOMONTH().