Convert text entered as minutes/seconds to minutes

[Kathie]

I have several entries (formatted as text) for example, :31, 1:04, 4:53,
23:34. These numbers indicate minutes and seconds (31 seconds, 1 hour 4
seconds, etc).
What formula can I use to convert these entries into seconds?

 

[Fred Smith]

If you really meant 1:04 is "1 hour 4 seconds", you've got problems, because
this is indistinguishable from the same entry meaning 1 minute, 4 seconds.
Assuming you meant the latter, use the following to convert to seconds:
=timevalue(a1)*60*24

Format as a number. The Timevalue function isn't really necessary, but I
like to use it because it makes the formula clearer to me.

Regards,
Fred