What is a cash book?
- By Book Keeping Pros
- Sources checked 15 Oct 2026
Definition
A cash book is a record of all the money a business receives and pays out, whether by cash, card, cheque or bank transfer, kept in date order. It shows the business's own view of its bank and cash balances, which a bank reconciliation then checks against the bank statements.
In a manual system, the cash book is a ruled book or a spreadsheet with columns for money received and money paid. In accounting software, the bank account register plays the same part: each bank transaction entered or imported is a cash book entry.
Each entry should be backed by the business's own documents, such as receipts and invoices. That evidence, not the way the entry was made, is what lets the cash book be checked against the bank statement.
In Australia
business.gov.au defines a bank reconciliation as a cross-check that the amounts in your cash book match the relevant bank statements.
It also says that if you use a single account for both personal and business banking, you must clearly identify any personal payments or expenses in your cash book.
Worked example
| Date | Details | Received (AUD) | Paid (AUD) | Balance (AUD) |
|---|---|---|---|---|
| 1 Jul 2026 | Opening balance | 2,000.00 | ||
| 3 Jul 2026 | Customer payment, invoice 104 | 880.00 | 2,880.00 | |
| 5 Jul 2026 | Rent | 1,200.00 | 1,680.00 | |
| 7 Jul 2026 | Office supplies | 95.50 | 1,584.50 |
Illustrative example only: these rows show the method and are not sourced data.
Common mistakes
- Copying bank transactions into the cash book without checking them against receipts, invoices and other supporting records.
- Leaving out small cash purchases because they seem too minor to record.
Related terms
Sources
- Key financial terms
business.gov.au, Australian Government. Current at 15 October 2026, released 9 July 2024. Checked 15 October 2026.
© Commonwealth of Australia 2020, licensed under CC BY 3.0 AU. Licence: CC BY 3.0 AU.
- Set up your business bank account
business.gov.au, Australian Government. Current at 15 October 2026, released 11 July 2024. Checked 15 October 2026.
© Commonwealth of Australia 2020, licensed under CC BY 3.0 AU. Licence: CC BY 3.0 AU.