Common mistakes with the trial balance

The trial balance lists every ledger balance in debit and credit columns to check that the two totals agree. The idea is simple, but there are two traps: knowing which side each balance goes on, and knowing what a balanced trial balance does and does not prove.

Both cost marks, and both are avoidable once you understand the logic behind the layout. Here are the mistakes we see most often.

Putting balances on the wrong side

Assets, expenses and drawings are debit balances. Liabilities, capital and income are credit balances.

The most frequent error is placing an item on the wrong side. Examples are drawings on the credit side, or returns inwards and returns outwards the wrong way round.

Returns inwards (from customers) are a debit. Returns outwards (to suppliers) are a credit.

Ask two questions of every item. First, what type of account is it: asset, expense, drawings, liability, capital or income?

Second, does that type normally carry a debit or a credit? The side then follows.

Some items do not announce their type. Carriage inwards is an expense (debit).

A provision for doubtful debts is a credit. Discount allowed is an expense, while discount received is income.

Believing a balanced trial balance means the books are correct

This is the biggest conceptual error. A trial balance can agree even when serious errors exist. Errors of omission, commission, principle, original entry, complete reversal and compensating errors all leave the totals equal.

In a theory question, never write that an agreed trial balance proves the accounts are free of error. It only proves that debits equal credits.

These errors hide because each still records equal debits and credits, just in the wrong place, at the wrong figure or not at all. The trial balance tests arithmetic, not classification.

A short worked illustration

These figures are invented to show the point. A business buys office equipment for RM4,000.

By mistake it debits general expenses instead of office equipment, and correctly credits the bank. General expenses are RM4,000 too high and office equipment is RM4,000 too low.

When the trial balance is drawn up, total debits still equal total credits, because RM4,000 has moved from one debit account to another. The trial balance agrees. Yet profit for the year is understated and a non-current asset is missing from the statement of financial position.

This is an error of principle. Re-adding the columns will not reveal it. Only a review of what each entry represents will.

Confusing the two kinds of error

Errors that make the trial balance disagree (a one-sided entry, an overcast, a wrong addition) are corrected through a suspense account. Errors that leave it agreeing are corrected by journal entry alone.

Students often force every correction through a suspense account, or open one when it is not needed. Ask whether the error, on its own, would have made the two columns unequal.

If yes, the correcting journal involves the suspense account. If no, because a debit and a credit were affected equally, the journal moves figures directly between the two accounts and suspense is not needed.

Forgetting closing inventory

Closing inventory does not appear in the trial balance drawn up from the ledger. It is worked out at the year end and brought in as an adjustment when preparing the financial statements.

Students sometimes list closing inventory in the trial balance, which is wrong. Opening inventory, by contrast, is a debit balance in the trial balance.

Closing inventory is deducted from purchases so that only the cost of goods actually sold is matched against the period’s revenue. It belongs in the income statement and the statement of financial position.

Listing the wrong figure for accounts with two-sided balances

A bank account can be a debit balance (money in the bank) or a credit balance (an overdraft). List whichever it actually is.

Assuming bank is always a debit is a common slip. A phrase such as “the business was overdrawn at the bank” tells you to put the bank balance on the credit side.

Missing the suspense account when totals disagree

If the trial balance does not agree and you cannot find the error quickly, enter the difference in a suspense account. This makes the trial balance balance for now.

Do not leave the totals unequal or force a figure. Clear the suspense account as you find the errors.

Presentation slips

Head the columns “Dr” and “Cr”, align the figures and total both columns. A neat trial balance makes a balance on the wrong side easier to spot and earns presentation marks.

Two quick checks can locate a difference. If the totals are out by an amount divisible by nine, suspect a transposition. If an item is on the wrong side, the totals differ by twice that item, so look for a balance equal to half the difference.

How to practise

Draw up short trial balances from a list of balances. Include items that are easy to misplace: drawings, returns, opening inventory and an overdraft. Then attempt theory questions on what a trial balance proves.

Do both. A student who can prepare a neat trial balance but cannot explain its limits will lose the theory marks. A student who can quote the theory but fumbles debits and credits will lose the practical ones.

If the trial balance still causes confusion, one of our teachers can go through the debit and credit rules and the treatment of errors with your child. Book a trial class to get started.

Syllabus reference: Cambridge 0452 and 0985, syllabus for 2027 to 2029, sub-topic 3.1 The trial balance (page 13).