With the data sorted you should choose Data | Subtotals, specifying
For Each Change in column A and choose SUM on Column C.

After Excel has calculated this, it will have inserted a new row after
each Well Number with a subtotal of column C for that Well.

Hope this helps.

Pete

On May 3, 6:50 pm, ndforty wrote:
I have extracted reports where oil well numbers are in column A and a related
expense is in column C. I'm looking for a function to that will give me
total expenses per well number.

I've sorted the spreadsheet by well number and then put sum formulas that
add all the column c expenses for a given well number out to the side, but
this is very tedious with over 100 well numbers.

Is there an easier way?