You've studied hard, you know the material, and then you open the exam paper and lose marks on things you actually understand. Sound familiar?
It's one of the most frustrating things about IGCSE Accounting. The subject rewards precision, and even small slips in how you present your answers, label your accounts, or interpret a question can cost you marks you deserved. The good news? Most of these errors are predictable. Once you know what to watch for, you can train yourself out of them.
Here are the mistakes that trip up IGCSE Accounting students most often, and exactly what to do instead.
1. Posting entries on the wrong side of the ledger
What students do
They memorise "debit the receiver, credit the giver" but then apply it inconsistently, especially when dealing with expenses, returns, or contra entries. A purchase return gets debited to the purchases account instead of credited, or a cash discount received ends up on the debit side of the discount received account.
Why it costs marks
In Paper 2, examiners award marks for each correctly posted entry. One wrong side means that entry scores zero, and it can also throw off your trial balance, costing you further marks downstream.
The correct technique
Before posting any entry, ask yourself two questions: which account is receiving value, and which account is giving value? The account receiving value is debited. The account giving value is credited. For expenses, think of it this way: when you pay rent, the rent account receives the cost (debit), and the bank account gives up cash (credit).
2. Forgetting to balance off ledger accounts
What students do
They post all the entries correctly but then leave the account hanging without a balance carried down (c/d) and balance brought down (b/d). Or they balance the account but put the closing balance on the wrong side.
Why it costs marks
The balancing entry is often worth a separate mark. Leaving it out means you've done 80% of the work but missed the final mark. In a question worth 4 marks, that's 25% of the available marks gone for no reason.
The correct technique
After posting all entries to an account, total both sides. The difference is your balance c/d, which goes on the smaller side to make both sides equal. Then bring the balance down (b/d) on the opposite side below the totals line. Always date it and label it clearly.
3. Misclassifying capital and revenue expenditure
What students do
They treat the delivery cost of a new machine as revenue expenditure, or they classify a major office refurbishment as revenue expenditure because it sounds like a regular expense. The classic trap is painting a building: if you're repainting it to its original condition, that's revenue expenditure. If you're converting a storage room into an office, that's capital expenditure.
Why it costs marks
Getting this wrong affects the profit figure and the value of non-current assets on the statement of financial position. Examiners specifically test whether you understand the distinction, and misclassification shows you don't.
The correct technique
Ask yourself: does this spending create a new asset or increase the earning capacity of an existing one? If yes, it's capital expenditure. Does it maintain the current earning capacity or cover day-to-day running costs? Then it's revenue expenditure. Installation, delivery, and legal fees for acquiring an asset are capital, not revenue.
4. Using the wrong depreciation method or making calculation errors
What students do
They apply the reducing balance method when the question specifies straight-line, or they forget to deduct the residual value before calculating. Another common error: using the original cost for year 2 of reducing balance instead of the net book value at the end of year 1.
Why it costs marks
Depreciation questions carry multiple marks, and the wrong method means every subsequent figure is incorrect. Even if your workings are logical, the examiner can only award "own figure" marks if your method is the one specified in the question.
The correct technique
- Straight-line: (Cost - Residual Value) / Useful Life = Annual Depreciation. The charge is the same every year.
- Reducing balance: Apply the percentage to the Net Book Value at the start of each year, not the original cost. Year 1 uses cost, year 2 uses (cost - year 1 depreciation), and so on.
5. Omitting narrations in journal entries
What students do
They write the debit and credit entries but skip the narration line underneath. Or they write something vague like "to correct error" without specifying what the error was.
Why it costs marks
The narration is often worth a separate mark. Cambridge mark schemes frequently state "1 mark for correct narration" as a distinct marking point. A journal entry without a narration is technically incomplete.
The correct technique
Every journal entry needs a brief, specific narration explaining the purpose of the entry. For error corrections, name the type of error. For example: "Being correction of an error of commission: payment to J. Smith wrongly posted to J. Smythe account." Keep it factual and specific.
6. Confusing the six types of errors that don't affect the trial balance
What students do
They mix up errors of commission and errors of principle, or they can't distinguish between errors of original entry and errors of complete reversal. When asked to identify an error type from a scenario, they guess rather than applying the definitions systematically.
Why it costs marks
Error identification questions are common in both Paper 1 and Paper 2. Getting the type wrong means the correction journal entry will also be wrong, potentially losing you marks across multiple parts of the question.
The correct technique
| Error Type | What Happened | Example |
|---|---|---|
| Commission | Correct type of account, wrong person/name | Payment to A. Ali posted to A. Ahmed |
| Principle | Posted to the wrong class of account | Motor repairs posted to motor vehicles account |
| Original entry | Wrong amount recorded from the start | Invoice for $450 recorded as $540 |
| Complete reversal | Correct accounts, correct amount, wrong sides | Cash sale debited to sales, credited to cash |
| Omission | Transaction not recorded at all | A credit purchase never entered in the books |
| Compensating | Two errors of equal amount cancel out | Sales overstated by $100, purchases also overstated by $100 |
7. Producing incomplete bank reconciliation statements
What students do
They start with the bank statement balance and adjust for unpresented cheques and outstanding lodgements, but they forget to first update the cash book for items that appear on the bank statement but not in the cash book, like direct debits, bank charges, and standing orders.
Why it costs marks
The bank reconciliation has two stages. If you skip the cash book update, your adjusted cash book balance will be wrong, and the reconciliation won't agree. Examiners look for both stages.
The correct technique
- Update the cash book first: add any receipts on the bank statement that the business hasn't recorded (e.g., direct credits, interest received). Deduct any payments the business hasn't recorded (e.g., bank charges, direct debits, dishonoured cheques).
- Find the adjusted cash book balance.
- Start the reconciliation statement with the bank statement balance.
- Add outstanding lodgements (money the business has recorded but the bank hasn't yet).
- Deduct unpresented cheques (cheques the business has issued but the bank hasn't yet processed).
- The result should equal the adjusted cash book balance from step 2.
8. Calculating accounting ratios with the wrong figures
What students do
They use revenue instead of cost of sales in the inventory turnover ratio, or they include long-term liabilities in the current ratio. Another frequent error is using closing capital instead of average capital for ROCE, or confusing mark-up (based on cost) with margin (based on revenue).
Why it costs marks
Ratio questions typically carry 2-3 marks each: one for the formula, one for the correct figures, and sometimes one for interpretation. Using the wrong figure in a correct formula gives you at most 1 mark out of 3.
The correct technique
| Ratio | Formula | Common Wrong Figure |
|---|---|---|
| Gross profit margin | Gross profit / Revenue x 100 | Using cost of sales instead of revenue |
| Mark-up | Gross profit / Cost of sales x 100 | Using revenue instead of cost of sales |
| Current ratio | Current assets / Current liabilities | Including non-current items |
| Acid test | (Current assets - Inventory) / Current liabilities | Forgetting to subtract inventory |
| ROCE | Profit for the year / Capital employed x 100 | Using opening capital instead of average |
9. Running out of time on Paper 2
What students do
They spend too long perfecting their answer to the first structured question and then rush through the remaining questions, leaving some parts blank or giving incomplete answers. Paper 2 has 120 marks in 90 minutes for the older format, or proportional time for current formats, and every minute matters.
Why it costs marks
The first few marks on any question are easier to earn than the last few. Spending 25 minutes chasing 2 extra marks on question 1 means losing 10 easier marks on questions you never reached.
The correct technique
Allocate time strictly by marks. If a section is worth 12 marks, spend roughly 12 minutes on it. When your time is up for that section, move on even if you haven't finished. You can return to incomplete answers if you have time at the end. The marks you pick up by attempting every question will almost always outweigh the marks you'd gain by perfecting one.
10. Giving vague interpretations instead of specific analysis
What students do
When asked to "comment on" or "suggest reasons for" a change in a ratio, they write something like "the profit has gone up which is good for the business" without referencing the actual figures or offering a plausible business reason.
Why it costs marks
Interpretation marks in IGCSE Accounting require you to use the data and give a reason. A generic statement doesn't demonstrate understanding. The mark scheme typically requires a specific observation linked to a possible cause.
The correct technique
Structure your interpretation in three parts: state what the ratio shows, compare it to the previous period or another business, and suggest a specific business reason. For example: "The gross profit margin has decreased from 35% to 28%, suggesting that cost of sales has increased relative to revenue. This could be due to higher raw material prices or the business offering more discounts to customers."
Your revision checklist
Before your next practice paper, run through these ten points. Better yet, keep this list next to you while you mark your own work. Most students make the same two or three mistakes repeatedly. Once you identify your personal patterns, you can fix them quickly.
- Check every T-account has a balance c/d and b/d
- Underline the depreciation method before calculating
- Write the formula before plugging in ratio figures
- Include a narration on every journal entry
- Update the cash book before starting the reconciliation
- Allocate time by marks, not by question difficulty
- Use figures and reasons in every interpretation answer
IGCSE Accounting rewards careful, methodical work. The students who do well aren't necessarily the ones who understand the most theory. They're the ones who make the fewest avoidable errors. And that's entirely within your control.
A breakdown of the ten most common mistakes IGCSE Accounting students make in exams, from posting entries on the wrong side to vague ratio interpretations. Each mistake includes the wrong approach, why it costs marks, and the correct technique to use instead.
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