Key Concepts
A trial balance is a list of all the account balances at a particular date, with the debit balances in one column and the credit balances in another. A business prepares one for two reasons:
- To check arithmetic accuracy in recording — that the figures add up correctly. If every transaction was recorded with equal debit and credit, the two totals should match.
- To help prepare the financial statements — the balances are all gathered in one place, ready to be sorted into the Statement of Financial Performance and the Statement of Financial Position.
A balanced trial balance is not an absolute proof of accuracy. It only proves one thing: that total debits equal total credits. Some mistakes leave both totals equal, so the trial balance still balances even though the records are wrong. These are the errors not revealed by the trial balance — the errors this chapter is about. Left uncorrected, they distort the profit and the Statement of Financial Position that are prepared from these records, so they must be found and put right.
The five errors not revealed by the trial balance. In each one, the debit still equals the credit, so the trial balance still balances, even though something has gone wrong.
| Type of error | What happened | Why the trial balance still balances |
|---|---|---|
| 1. Wrong amount recorded | Recorded on the correct sides and in the correct accounts, but at the wrong figure — debit and credit share the same wrong figure (e.g. a $1,200 sale entered as $120). | The debit and the credit are still equal (both $120), so the totals still match. |
| 2. Not recorded at all | The transaction was left out entirely — no debit and no credit was made. | Nothing was added to either column, so both totals are unaffected. |
| 3. Recorded in wrong account (different element) | The right amount and sides, but one entry was posted to an account of a different accounting element (recall the five elements — assets, liabilities, capital, income, expenses). For example, repairs to a motor vehicle (an expense) recorded as the motor vehicle itself (an asset). | A debit is still a debit of the same amount; only which account it sits in is wrong, so the totals still match. |
| 4. Recorded in wrong account (same element) | Posted to the wrong account of the same accounting element — for example, a credit sale to one customer posted to another customer's account (both are trade receivables). | One account is too high and another of the same element is too low by the same amount, so the column total is unchanged. |
| 5. Recorded on wrong sides (reversed entry) | The correct accounts and amount, but the debit and credit were swapped — the account that should have been debited was credited, and the account that should have been credited was debited. | There is still one debit and one credit of equal amount, so the totals still match. |
Notice what every row has in common: the debit still equals the credit, so the trial balance's one and only check is passed. That is exactly why these errors slip through.
A trial balance asks "do the two totals match?" — not "is every entry right?" Five slip-ups keep the totals matching, so they escape it: a wrong amount recorded, a transaction not recorded at all, the wrong account of a different element, the wrong account of the same element, and the wrong sides recorded.
Believing a balanced trial balance means the books are error-free. It only proves debits equal credits. All five errors above can be present while the trial balance still balances.
Confusing these with errors that would unbalance the trial balance. Errors such as recording only one side of a transaction, or adding a column up wrongly, do make the totals fail to match — but those are not in this chapter's scope. Here, every error keeps the trial balance balanced.