Calculate Percentage change

Anonymous , is it Month vs Month or Day Vs Day, You can use time intelligence in a given manner with time table

MTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESMTD('Date'[Date]))
last MTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(dateadd('Date'[Date],-1,MONTH)))
last MTD (complete) Sales =  CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(ENDOFMONTH(dateadd('Date'[Date],-1,MONTH))))
last year MTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(dateadd('Date'[Date],-12,MONTH)))
last year MTD (complete) Sales =  CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(ENDOFMONTH(dateadd('Date'[Date],-12,MONTH))))
Month behind Sales = CALCULATE(SUM(Sales[Sales Amount]),dateadd('Date'[Date],-1,Month))
last QTR same Month (complete) Sales =  CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(ENDOFMONTH(dateadd('Date'[Date],-1,Qtr))))
MTD (Year End) Sales =  CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(ENDOFYEAR('Date'[Date])))
MTD (Last Year End) Sales =  CALCULATE(SUM(Sales[Sales Amount]),DATESMTD(ENDOFYEAR(dateadd('Date'[Date],-12,MONTH),"8/31")))


diff = [MTD Sales]-[last MTD Sales]
diff % = divide([MTD Sales]-[last MTD Sales],[last MTD Sales])

To get the best of the time intelligence function. Make sure you have a date calendar and it has been marked as the date in model view. Also, join it with the date column of your fact/s. Refer :
https://radacad.com/creating-calendar-table-in-power-bi-using-dax-functions
https://www.archerpoint.com/blog/Posts/creating-date-table-power-bi
https://www.sqlbi.com/articles/creating-a-simple-date-table-in-dax/

See if my webinar on Time Intelligence can help: https://community.powerbi.com/t5/Webinars-and-Video-Gallery/PowerBI-Time-Intelligence-Calendar-WTD-YTD-LYTD-Week-Over-Week/m-p/1051626#M184
https://community.powerbi.com/t5/Community-Blog/Decoding-Direct-Query-in-Power-BI-Part-1-Time-Intelligence-in/ba-p/922885

Appreciate your Kudos.