How to list multiple, repeating times in a column?

[afre1996]

Hi

I need to make an Excel sheet to make an animal observation paper. The list requires to observe the animals every 30 seconds so the list would look something like:

8:25 am
8:25 am
8:26 am
8:26 am
8:27 am
8:27 am
etc...

Is there a shortcut on how to make these times without having to manually typing each row?
Thanks!

 

[MARZIOTULLIO]

Hi

Format column a as time


A1=8:25 am


A2=IF(COUNTIF($A$1:A1,A1)=1,A1,A1+1/1440) copy down

 

[afre1996]

Hi

Format column a as time


A1=8:25 am


A2=IF(COUNTIF($A$1:A1,A1)=1,A1,A1+1/1440) copy down

I have tried, but nothing happens.

 

[Joe4]

I have tried, but nothing happens.

Surely, something happens (maybe not what you expect), but if you place the formula in cell A2 and copy down, something will show up in those cells.
What exactly are you seeing in these cells?
Note that you may have a fractional number displaying. That is because Date/Time are stored as mumbers (specifically the number of days since 1/1/1900).
So you will need to change the format to a Time format to see the times like you are accustomed to seeing.

 

[mikerickson]

Recursivly adding 30 seconds will get round off error pretty quickly. A cleaner formulation would be in A2

=$A$1+ROWS($1:1)*TIME(0,0,30)

and drag down. (The round off doesn't accumulate)

 

[afre1996]

Recursivly adding 30 seconds will get round off error pretty quickly. A cleaner formulation would be in A2

=$A$1+ROWS($1:1)*TIME(0,0,30)

and drag down. (The round off doesn't accumulate)

Your formula worked and really helped! This will greatly help in my research! Thank you so much!