How do I calculate the average of a column so that it automatically changes?

Hello,


I currently have a column for times similar to this:
3:05
3:06
3:10
2:20
Average: 2:52

How would I be able to add a new time below 2:20 so that the average changes automatically?

Average only calculates on cells with values in them.
So if the times were in column A and the average in another column
=average(A:A)

would suffice

Thanks to both of you! I got an error from the other one, might be a translation error (god I hate Finnish Excel, full of words I've never even heard of). I'll just put the average on another column.