On Aug 17, 1:24 pm, bgetson wrote:
Maybe it would make more sense if I phrase my problem a different way.

I have a table full of data that is sorted in ascending order based on
time. There is a row of initial conditions at the top of the table so
that my recursive formulas can reference the previous time interval
and evalulate change.

I am creating a macro that will restrict my data based on a time
interval that I create (through a user form), with the ultimate goal
of updating the first non-filtered row so that it references the
initial conditions (instead of the hidden row above it).

What would be the best way to go about this?

I would still move the initial conditions above the table - just so it
never gets hidden by your filter, and because it really isn't part of
your data. It sounds like you may need to do your calculations in VBA.
I'm not sure how you'd manage skipping over hidden rows in your data
with a formula in a sheet. In VBA you could loop through your data
and on the first visible row use the initial values and on subsequent
visible rows use the previous visible rows values. If you've found a
way to do a similar process in an Excel formula I'd love to see it,
always looking to add something to my toolkit.