Two-thirds penalty (2/3) calculator
Two-thirds of the marks for a correct answer is deducted for each wrong answer. Enter your question counts to review expected value and penalty trade-offs.
Estimate your score.
Enter your responses to calculate net marks and penalty deductions.
60 correct · 20 wrong · 20 unattempted
60.00
−13.33
75.00%
80.00%
How this penalty is calculated
Two-thirds of the marks for a correct answer is deducted for each wrong answer. These are editable defaults for a scoring estimate. Confirm the rule for the exact examination, paper, and cycle before applying it.
| Value | Default | Meaning |
|---|---|---|
| Correct response | +1 mark | Added per correct answer |
| Wrong response | −0.6667 marks | Deducted per wrong answer |
| Blank response | 0 marks | No correct or wrong response entered |
Score calculation formula
Net score = (correct × 1) − (wrong × 0.6667)
Example: 6 correct and 2 wrong yields 4.67 marks before official normalization or section qualifying rules.
Expected value when eliminating choices
Expected value = (chance correct × positive marks) − (chance wrong × penalty). Break-even accuracy with these settings is 40.00%.
| Choices left | Chance correct | Expected marks | Estimate |
|---|---|---|---|
| 4 of 4 | 25.0% | -0.25 | Negative expected value |
| 3 of 4 | 33.3% | -0.11 | Negative expected value |
| 2 of 4 | 50.0% | +0.17 | Positive expected value |
| 1 of 4 | 100.0% | +1.00 | Positive expected value |
This is a mathematical probability estimate under uniform assumption, not official test strategy.
Frequently asked questions
How does the two-thirds penalty affect my score?
This calculator awards +1 mark per correct answer and deducts 0.6667 marks for each incorrect response. Blank answers receive 0 marks.
What is the break-even guessing threshold for this penalty?
With 4 options, break-even accuracy is 40.00%. With four equally likely options, eliminate at least two options to reach positive expected value.
Which competitive exams use this penalty?
Common exams following this penalty structure include: Custom scoring. Use our dedicated exam calculators for paper-specific rules.
What is the net score formula?
Net Score = (Correct Answers × 1) − (Incorrect Answers × 0.6667). Example: 70 correct and 15 wrong yields 60.00 marks.
Expected value when eliminating choices
Expected value = (chance correct × positive marks) − (chance wrong × penalty). Break-even accuracy with these settings is 40.00%.
| Choices left | Chance correct | Expected marks | Estimate |
|---|---|---|---|
| 4 of 4 | 25.0% | -0.25 | Negative expected value |
| 3 of 4 | 33.3% | -0.11 | Negative expected value |
| 2 of 4 | 50.0% | +0.17 | Positive expected value |
| 1 of 4 | 100.0% | +1.00 | Positive expected value |
This is a mathematical probability estimate under uniform assumption, not official test strategy.
Frequently asked questions
How does the two-thirds penalty affect my score?
This calculator awards +1 mark per correct answer and deducts 0.6667 marks for each incorrect response. Blank answers receive 0 marks.
What is the break-even guessing threshold for this penalty?
With 4 options, break-even accuracy is 40.00%. With four equally likely options, eliminate at least two options to reach positive expected value.
Which competitive exams use this penalty?
Common exams following this penalty structure include: Custom scoring. Use our dedicated exam calculators for paper-specific rules.
What is the net score formula?
Net Score = (Correct Answers × 1) − (Incorrect Answers × 0.6667). Example: 70 correct and 15 wrong yields 60.00 marks.