On Sunday, August 5, 2012 9:50:16 PM UTC-7, Mohammad Salman wrote:
Suppose I have a expense head Internet and have Internet budget say 10000 for a year..

My sheet shoud work like

Sno. | Voucher No. | Head | Amount | Budget remaining
1 | V74 | Internet | 3000 | 7000

Means when every I put an expense "Budget remaining" column should show
me the remaining budget.

I'm assuming that the worksheet has only Internet expenses, with other categories elsewhere. If categories are intermixed, it's more complicated, but doable.

My suggestion is to put the yearly budget of 10000 in E2 under "Budget Remaining." The entry in B2 could say "Starting Balance" or something similar (it's not a voucher).

The first voucher would be in row 3.

To calculate the budget remaining in E3, put
=E2-D3
Copy this formula down as far as needed for new vouchers.

Hope this helps getting started.