The Trial Balance does not show accuracy in ledger account, is not absolute proof of the accuracy. It is just a proof only of the arithmetical accuracy of the postings involved. Sometimes, the total of debits side may be equal to the total of credits side yet still there may be errors.
This is a list of 6 errors not revealed by trial balance
1. Errors Of Omission
The error of omission refer to a case where a transaction is completely omitted from the books. If we sold goods worth $100 to B Uta and omitted to record the transaction in the books the trial balance will still balance. This is so because the credit and debit balances are understated by $100
ALSO READ: Rules, Uses and Nature Of Trial Balance
2. Errors Of Commission
Error of Commission occurs when the correct amount is entered into an account of the right class (e.g. Personal Accounts in the Credit Ledger) but in the wrong account. For example we sold goods worth $60 to R Moyo but enter the transaction as a sale of goods worth $60 to S Moyo. surprisingly, the trial balance will always balance in such cases
3. Errors Of Principle
Error of principle is when the right amount of a transaction is entered into the correct side of the wrong class in the account. For instance, the purchase of a motor vehicle (fixed asset) is recorded in the Motor Vehicle Expenses Account (a revenue expenditure account)
4. Compensating Errors
This is when two or more errors of equal amounts occur on both sides. For example the Sales figure(credit side) is understated by $700 while the Fixed Asset Account (debit balance) is understated by the same amount such errors will cancel each other
ALSO READ: Types Of Accounting
5. Complete Reversal Of Entries
Where the correct accounts are used but each item is shown on the wrong side of the account. For example a receipt of $400 cash from R Kudada a debtor is recorded by Debiting R Kudada and Crediting Cash (the opposite of what it should be) the trial balance will still agree.
6. Transposition Errors
Transposition errors is where the wrong sequence of the individual characters within a number was entered. For example $143 is recorded as $134. This will likely occur when the error occurs in books of original entry.
None of these errors explained above can be disclosed by Trial Balance as a Trial Balance will always agree i.e. the Credit and Debit balance will always be the same after calculation.