Automatic numbering by category

[oteixeira]

I don’t think there is a way of putting this to work without VBA but let’s see…
In the uploaded worksheet user will choose the Category in Column B, according to the data validation of the ‘sublist’ named range. If there is no chosen Category (column B is empty), no automatic numbering should be used. If there is a chosen Category then the automatic and sequential numbering should occur on column C as mocked up in the worksheet.
Many thanks in advance for any kind help.
Octavio

[Phuocam]

Try this in C3:

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

[Fluff13]

How about
=IF(B3="","",COUNTIF(B$3:B3,B3))

[oteixeira]

Perfect! Many thanks to both.

[Fluff13]

You're welcome & thanks for the feedback