The sales day book is a manually-maintained ledger in which is recorded the key detailed information for each individual credit sale to a customer, including:
- Customer name
- Invoice number
- Invoice date
- Invoice amount
This information is usually added to the sales day book at the end of each business day, based on the company's copies of all customer invoices issued.
The daily total of the sales listed in the sales day book is then transferred into the sales ledger. Thus, the most detailed recordation of credit sales is the sales day book, with only daily totals of credit sales appearing in the sales ledger.
The sales day book is only used in manual accounting systems. It is not used in computerized accounting systems, since accounting software automatically stores and aggregates all customer invoices prepared through the computer system; there is no need to prepare a sales day book.
The sales day book is also known as the sales book.