Hi Nitya.

Am Thu, 14 Apr 2016 02:45:54 -0700 (PDT) schrieb Nitya Satheesh:

So sorry for the late reply and thank you for your result.The code you have given me calculates the minimum period for each species. What I needed was the minimum period in which i get all the species together.I am so sorry i haven't been able to explain this better. Is there anyway i can modify the formula you have given me so that it encompasses the whole set of species?

try:
=SMALL(A2:A100,SUMPRODUCT((B2:B100<"")/COUNTIF(B2:B100,B2:B100&""))*2)-SMALL(A2:A100,1)+1


Regards
Claus B.
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