With all due respect, you then do not need Excel? If it has to reset to 0
every day, then what is the purpose of having a spreadsheet? You will have
no records whatsoever after a month, as you will still have only one days
statistics. You cannot audit, you cannot do stock control, you cannot
establish trends, or do anything useful with that kind of data.
If you say you have a number of products, then your sheet has been set up
incorrectly. If this is the case, I would suggest you use Col A as a date
column, Col B as receipts, C as shipments and D as totals for product 1, Col
E, F and G for product 2 etc.
Use Row 1 to enter the names of the various products. You can merge B1

1,
E1:G1 etc to make it look nice.
In D2 enter =IF($A2="","",B2-C2). Copy this to Cols G, I, L etc
In D3 enter =IF($A3="","",D2+B3-C3). Copy this across as above, and also
down as far as needs be.
After a month, you will at least have a month's worth of data, which you can
use in so many ways, to establsih trends - Mondays you sell more of item A
then on every other weekday, which means you have to order more for Mondays,
or something to that effect, or that sales on tiem 3 is dwindling, and you
should consider stopping this line - you know......
You will be bale to see how much stock you have, and how your stock
increased and why. You will be able to establish where losses occured. You
name it