Row number automatication formula

[Pulleritz]

Hello,

Need help with this formula:

1. I have one column for project and second column for row nr calculation. Formula should calculate number by logic: if itīs first row, then calculate 1, if itīs second row of this project previous row + 1. Problem is sometimes, I need to start not from 1 but for example from 8 (I will manually overwrite formula to 8) and next row should calculate 8 +1 =9. Added excel also.

Projekt Number
A 1 I tīs first row for this project, automatically set 1.
B 8 itīs first row for this project, automatically set 1, but it this project neet to manually change 8
A 2 itīs second row for this project, set previous number + 1
A 3 itīs third row for this project, set previous number + 1
C 1 itīs first row for this project, automatically set 1.
B 9 itīs second row of this project, set previous number + 1

Thanks.

[Bo_Ry]

Please try at C3 and drag down

=COUNTIF(B$3:B3,B3)+(B3="b")*7

or

=AGGREGATE(14,6,N(+C$2:C2)*(B$2:B2=B3),1)+1

[Pete_UK]

You can use this formula in C3:

=COUNTIF(B$3:B3,B3)+IF(B3="B",7,0)

then copy down. If you have a lot of projects with a starting point other than 1, it would be better to set up a table with those starting points and use VLOOKUP instead of the IF.

Hope this helps.

Pete

[Pulleritz]

Aggregate formula works fine. Thanks