Sales and Purchase Ledgers Explained

Sales and purchase ledgers are the two records that show who owes your business money and who your business owes. The sales ledger tracks invoices to customers and the payments you receive; the purchase ledger tracks bills from suppliers and the payments you make. Kept up to date, they help you chase cash on time, pay suppliers correctly and give your accountant accurate figures at the year end. This guide explains how each ledger works, how to keep them tidy and the mistakes that cause most problems.

Key takeaways

• The sales ledger shows money owed to you; the purchase ledger shows money you owe.
• Every invoice, bill, payment and credit note should go into the right ledger.
• Aged debtor and creditor reports turn the ledgers into a cash flow tool.
• Bookkeeping software keeps the ledgers automatically, but only if you enter everything.
• Reconcile the ledgers with your bank at least monthly.

What is a ledger?

A ledger is a running record of transactions grouped together for one purpose. In bookkeeping, the sales ledger (sometimes called the accounts receivable or debtors ledger) holds an account for each customer, and the purchase ledger (accounts payable or creditors ledger) holds an account for each supplier. Each account shows invoices or bills, payments and the balance still outstanding. The totals feed into your main accounts as trade debtors and trade creditors on the balance sheet.

Keeping accurate records is a legal requirement for every business. GOV.UK sets out what limited companies must keep and what sole traders must keep. Ledgers are a practical way of meeting those rules when you trade on credit.

Sales ledger and purchase ledger compared

How the sales ledger works

When you raise an invoice, it is posted to the customer's account in the sales ledger and increases what they owe. When the customer pays, the payment is matched to the invoice and the balance falls. If you issue a credit note, for example for a returned item, it reduces the balance too. Our guide to invoice numbering and credit notes explains how to keep that sequence clean.

The aged debtors report built from the sales ledger is one of the most useful documents in a small business. It shows exactly which invoices are overdue and by how long. If a business customer pays late, you may be able to claim statutory interest; GOV.UK explains the rules on late commercial payments, and our article on chasing late payments covers the practical steps.

How the purchase ledger works

When a supplier bill arrives, enter it in the purchase ledger against that supplier, with the date, amount, any VAT and the due date. When you pay, match the payment to the bill. This gives you a list of what is due and when, so you can plan payments, take advantage of any early payment terms and avoid paying the same bill twice. Comparing your purchase ledger with supplier statements each month quickly shows any missing bills or payments.

Step-by-step: keeping your ledgers up to date

1. Raise invoices promptly in your software as soon as work is done, using a consistent numbering sequence.
2. Enter supplier bills on arrival, not when you pay them, so the purchase ledger shows what you really owe.
3. Match bank payments to the correct invoice or bill when you reconcile. See our guide to bank reconciliation.
4. Post credit notes against the original invoice or bill rather than deleting anything.
5. Run aged debtors and creditors reports monthly and act on them.
6. Check supplier statements against your purchase ledger and resolve differences.
7. Review old balances at the year end, so your accountant can deal with any debts that will not be paid.

Worked example (illustrative example)

Illustrative example only, not a real business. A small limited company running a design studio invoices clients on 30-day terms and buys printing and software from four suppliers. At the end of September its sales ledger shows £14,600 owed by six clients, and the aged debtors report shows £3,900 of that is over 60 days old, all from one client.

Its purchase ledger shows £2,750 owed to suppliers, with £1,200 due to the printer within seven days. Using both reports, the director chases the overdue client first, schedules the printer payment for its due date, and notices that one software bill had been entered twice. Deleting the duplicate reduces the creditors figure to £2,500. Without ledgers, the overdue debt and the duplicate bill could easily have been missed until the year end.

Common mistakes

• Recording only bank receipts. If invoices are not entered, the sales ledger cannot show what is still owed.
• Unmatched payments. Money received but not matched to an invoice leaves both an unpaid invoice and an unexplained receipt.
• Deleting invoices. Use a credit note instead, so the audit trail stays intact.
• Paying from statements without checking. This is how duplicate and incorrect payments happen.
• Ignoring old balances. Very old debts or credits usually point to an error that is easier to fix sooner rather than later.

If your ledgers have fallen behind, our catch-up bookkeeping guide explains how to rebuild them in order.

How we can help

We are a London-based specialist accounting practice with fixed monthly fees. Our bookkeeping service starts from £150 per month and includes keeping your sales and purchase ledgers up to date, reconciling your bank and producing clear aged debtor and creditor reports. See our bookkeeping service, check our pricing, or contact us.