The trial balance, explained

The trial balance is the humble workhorse of accounting — a plain list that quietly proves the books hang together. Understand what it is and what it can and can’t tell you, and a lot of “is this file right?” anxiety goes away.

What it is

A trial balance lists every account and its current balance, in two columns — debits and credits. Because every transaction posts equal debits and credits (that’s double-entry), the two columns should total to exactly the same number. If they do, the books are “in balance.”

Why it must balance

The trial balance is really the accounting equation checked as a list. When total debits equal total credits, every transaction has both its sides recorded. When they don’t, a transaction was posted one-sided, or a value was entered on the wrong column — and the difference points you toward it.

What it catches — and what it doesn’t

A trial balance catches arithmetic imbalance: unequal debits and credits. It does not catch a transaction posted to the wrong (but still-balancing) account, a transaction missed entirely on both sides, or a right-amount-wrong-account error. So a balanced trial balance is necessary, not sufficient — it proves the mechanics, not the judgement.

Why it’s the first thing to check after an import

After a migration, the source trial balance and the destination trial balance should match account by account. If they don’t, the import is unfinished — and the gap is your fastest route to the problem (see why a trial balance won’t match after an import).