running balance with blank cells under empty field

hi guys

I made the following running balance

column A is deposits
column B is withdrawal
Column C is balance


i used the following formulas

C1 =SUM(A1,-B1)
C2 =SUM(C1,A2-B2)
C3 =SUM(C2,A3,-B3)
etc

Column C keep showing balance data even if A2, B2 are empty.

I am unable to find a formula for C3, C4 etc to stay blank until value gets entered in (A2 or B2) (A3 or B3) etc.

thanks again as this is great help

Try this in C2, and copy down:

=IF(AND(A2="",B2=""),"",C1+A2-B2)

HTH,
Jason

Jason, thanks, it works like a charm
and thanks for the quick reply, this forum is great

Disappointed. I tried Jason's solution for a check register. The last line's running balance reproduces downwards endlessly.
I double verified the formula copy.