transaction

In accounting, a transaction is any event that changes a business's financial position and can be measured in money. Selling a product, paying wages, borrowing from a bank, buying a desk — each is a transaction because it shifts what the business owns or owes by a definite dollar amount. It is the trigger: every recording in the books starts with a transaction having occurred.

Two tests decide whether something is an accounting transaction. First, does it affect the accounting equation — does it change assets, liabilities, or equity? Second, can it be reliably measured in money? Paying 600 dollars rent passes both: cash (an asset) falls by a clear 600. By contrast, hiring a promising new manager, however important, is not yet a transaction — nothing has changed hands and no amount has been exchanged; only when wages are actually paid does a transaction occur. Each qualifying transaction is then analyzed and recorded as a balanced journal entry.

Distinguishing real transactions from mere events is the first judgment in bookkeeping, often based on a source document like an invoice or receipt that proves it happened. The discipline matters because recording non-transactions (like a signed but unfulfilled contract) would put speculative numbers on the books, while missing a true transaction would understate reality. Everything downstream — entries, ledgers, statements — depends on correctly identifying what counts as a transaction in the first place.