How does a bar code help supermarket levels?

Answer 1

When an item is scanned at the till - the till communicates with the store's central stock computer - deducting the item from the stock list. At the end of the day, the manager can get a print-out of everything that's been sold that day, and the computer can calculate which items need to be re-ordered. That way - the staff only order what's actually needing to be restocked.

Answer 2

They allow the supermarket to, instead of typing the number in, just scan the items quickly which also allows the customer to leave faster. The bar codes also show the items bought and stock left in the store, which aids in ordering more stock.