Custom KPI card - difference based on the previous month

Hi , TornDigorn 

According to your descriptin, you want to custom the KPI card , and you want to show the differnce and the percentage in KPI card.

After my test, KPI displays Value and Goal by default, and there is no Difference:

So for your need , you can follow this to create a custom KPI card:
Custom KPI card in Power BI - Data Bear - Power BI Training

 

And i can give your the dax code to get the  differnce and the percentage:

Difference = var _date = MAX('Table'[Date])
var _t = FILTER( ALL('Table'), YEAR('Table'[Date]) = YEAR(_date) && MONTH('Table'[Date])=MONTH(_date)-1)

return
CALCULATE( AVERAGE('Table'[Final Days]) ,  YEAR('Table'[Date]) = YEAR(_date) , MONTH('Table'[Date])=MONTH(_date)) - AVERAGEX(_t,[Final Days])

Percentage = var _date = MAX('Table'[Date])
var _t = FILTER( ALL('Table'), YEAR('Table'[Date]) = YEAR(_date) && MONTH('Table'[Date])=MONTH(_date)-1)

return
DIVIDE(CALCULATE( AVERAGE('Table'[Final Days]) ,  YEAR('Table'[Date]) = YEAR(_date) , MONTH('Table'[Date])=MONTH(_date)) - AVERAGEX(_t,[Final Days]) ,AVERAGEX(_t,[Final Days]))

 

The result is as follows:

 

 

Thank you for your time and sharing, and thank you for your support and understanding of PowerBI! 

 

Best Regards,

Aniya Zhang

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