Is there a way to have a formula dynamically select the end of a list.

For example I have a list in Col A that can range from 10 - 5000
entries. I want to dynamically sum this (without always just selecting
the max size because there is information below the list). I also want
to use a formula instead of a list or pivot table.

In visual basic the selection would be something like:
SUM (Range(Range("A1"),Range("A1").End(xldown)))

Any ideas?