Double-entry bookkeeping
An accounting method in which every financial transaction is recorded in at least two accounts — a debit in one and an equal credit in another — so the books always balance and errors are easier to spot.
Also: double-entry
Every transaction has two sides. When your business pays a £600 supplier invoice, Xero records a £600 credit to your bank account (money leaves) and a £600 debit to the relevant expense account — say, Office Supplies. The totals cancel out. That balance is the foundation of double-entry, a system that has been standard practice for centuries because it makes errors visible: if debits and credits do not agree, something has gone wrong.
Xero enforces double-entry automatically. You rarely see the underlying journal entries when you reconcile a bank line or raise an invoice, but the system creates them for every action. Post a sales invoice for £1,200 plus VAT and Xero debits Accounts Receivable by £1,440, credits Sales by £1,200, and credits VAT Liability by £240 — three legs, all in balance.
Why it matters at month-end
The trial balance is the proof that double-entry has held throughout the period: total debits equal total credits across every account. If it is out, there is a posting error somewhere — a manual journal with one side missing, a deleted transaction, or an import that landed on one account only. Correcting those errors is usually the first task of a month-end close, and a clean trial balance is the prerequisite for a reliable profit and loss and balance sheet.