Slow ranking formula with multiple criteria

[bat18]

I have an issue where a ranking formula using multiple criteria is slowing my spreadsheet to a halt every time i change the input formula.

The formula is as follows:

=SUMPRODUCT(--($B$6:$B$18222=B6), --($CI6<$CI$6:$CI$18222))+1

Now the column CI6 is another formula that changes depending on what month is picked from a list. So each time a different month is picked all the values in column CI change.

This then changes the rank which takes around 3 minutes to complete. I was wondering if there was a quicker formula than the one i am using or a way of combining the above formula with an index(match) formula be using in column CI.

Any info would be greatly appreciated

 

[norulen]

I dont really know what does your input and output formula looks like but you can probably give Sumif formula a try