Negative marking calculator

Every scheme of this kind is two multiplications and a subtraction. Correct answers earn, wrong answers cost, and questions you left untouched do neither:

The number of wrong answers is not something you enter, it is derived, because it has to be what you attempted minus what you got right:

Accuracy is measured against what you attempted, not against the whole paper, because it is meant to answer how reliable you were when you committed to an answer. How much of the paper you took on is reported separately as the attempt rate.

A fractional penalty is a fraction of the marks for one correct answer. With 1/3 negative marking, the deduction per wrong answer is marks per correct answer divided by 3. With 1/4 negative marking, divide by 4. Enter that deduction in the penalty field and check your paper’s instructions.

If a correct answer earns 3 marks and the penalty is 1/3, a wrong answer deducts 1 mark. With 20 correct answers and 6 wrong answers, the score is (20 x 3) - (6 x 1) = 54 marks. If a correct answer earns 1 mark, the same 1/3 scheme deducts one third of a mark instead.

Under 1/4 negative marking with 4 marks per correct answer, each wrong answer deducts 1 mark. Under a scheme worth 1 mark per correct answer, each wrong answer deducts 0.25. Do not enter 0.25 for every 1/4 scheme: the value depends on the marks awarded for a correct answer.

Guessing is worth it exactly when the marks you expect to gain beat the marks you expect to lose. Write your hit rate as a, and guessing breaks even when:

Rearranged, the break-even hit rate is:

Under a scheme awarding 4 with 1 deducted, that is 1 divided by 5, or 20%. Under 1 with 0.25 deducted it is 0.25 divided by 1.25, which is also 20%. Both schemes have the same shape, which is why they feel the same to sit even though the numbers look different.

A blind guess among four equally likely options has a 25% hit rate. That is above the 20% break-even rate in the 4-with-1 and 1-with-0.25 examples, but exactly at break even under a one-third penalty scheme. Eliminating options can improve the hit rate. This model assumes one correct option, zero marks for skipped questions, and the scheme you entered; it is not a guarantee about your score or any particular exam.

Attempting everything on a paper you do not know is how a total goes negative. Take 100 questions with 1 mark for a correct answer and 0.25 off for a wrong one, all 100 attempted and 10 correct. You earn 10 and lose 90 times 0.25, which is 22.5, so the score is minus 12.5.

This calculator prints that negative figure rather than clamping it to zero, because a paper that deducts more than you scored is exactly the situation worth seeing clearly. Whether the official result floors at zero is a rule of the exam, and it does not change the arithmetic.

What does 1/3 negative marking mean?

For each wrong answer, deduct one third of the marks awarded for a correct answer. If a correct answer earns 3 marks, the penalty is 1 mark; if it earns 1 mark, the penalty is one third of a mark. Use your paper’s instructions to confirm the scheme.

How do I calculate 1/4 negative marking?

Divide the marks for one correct answer by 4 to get the penalty per wrong answer. With 4 marks per correct, deduct 1 per wrong; with 1 mark per correct, deduct 0.25. Multiply correct answers by the award and subtract wrong answers multiplied by that penalty.

How is a score with negative marking calculated?

Multiply the number of correct answers by the marks each correct answer earns, then subtract the number of wrong answers multiplied by the penalty for each wrong answer. Questions you left blank score nothing and cost nothing under the schemes this page models.

What marking scheme should I choose?

Use the one printed in your own exam's instructions. The presets here are common patterns, such as four marks for a correct answer with one deducted for a wrong one, offered as starting points rather than as any particular exam board's official rule. Marking schemes change between sessions and between papers, so read the paper.

Can my score go negative?

Yes, if the penalties outweigh what you earned. The calculator shows the negative figure rather than clamping it to zero, because a paper that deducts more than you scored is exactly the situation worth seeing clearly. Whether your exam floors the total at zero is a rule of that exam, not of the arithmetic.

How many questions do I need to guess right for guessing to be worth it?

Break even is where the marks gained equal the marks lost, which works out as the penalty divided by the sum of the penalty and the marks per correct answer. Under a scheme awarding four with one deducted, that is one in five, or 20% accuracy. Above that rate guessing gains marks on average, below it guessing costs marks. The calculator prints this figure for whatever scheme you enter.

What is accuracy here?

Correct answers divided by attempted answers, as a percentage. It deliberately ignores the questions you skipped, because it measures how reliable you were when you did commit to an answer. The attempt rate is shown separately.

Is this calculator free?

Yes. It runs in your browser, needs no account, and nothing you enter leaves your device.