Test Score Calculator
Turn the number of correct answers into a percentage score and letter grade.
Results update as you type.
About this calculator
A test score calculator converts the number of questions you got right out of the total into a percentage and a letter grade. Enter how many you answered correctly, or switch to entering how many you got wrong and it works out the rest. If wrong answers carry a penalty — some standardized exams deduct a fraction of a point to discourage guessing — set the points lost per wrong answer under advanced options; otherwise every wrong or blank question simply scores zero.
Worked example: 18 correct out of 20 is 18 ÷ 20 × 100 = 90%, an A-. If instead a quarter-point penalty applied to the 2 wrong answers, the raw score would be 18 − 0.25×2 = 17.5, giving 17.5 ÷ 20 = 87.5%, a B+.
A reference table shows exactly where each percentage falls on the letter scale. Teachers use it to grade quizzes and set curves, and students use it to check a score before results are posted or to see how many more questions they need right to reach the next grade.
Frequently asked questions
How do I calculate a test percentage?
Divide the number of correct answers by the total number of questions and multiply by 100. Eighteen correct out of twenty is 18 ÷ 20 × 100 = 90%.
Can I enter the number I got wrong instead?
Yes — set the mode to “Number wrong” and type how many you missed. The calculator subtracts that from the total to find how many you got right, then works out the percentage the same way.
How does the wrong-answer penalty work?
Some exams subtract a fraction of a point for each wrong answer to discourage guessing. If you set a penalty, it is multiplied by the number of wrong answers and removed from your raw score before the percentage is worked out.
How many questions can I get wrong and still pass?
Divide the passing percentage you need by 100 and multiply by the total to get the minimum correct answers, then subtract from the total. To keep a 70% pass on a 20-question test you need 14 right, so you can miss at most 6.
What test score do I need for an A?
On the common scale an A starts at 90%. Multiply 0.90 by the number of questions and round up: on a 50-question test you need 45 correct for an A, 40 for a B and 35 for a C.
Does a blank answer count the same as a wrong one?
By default yes — any question not answered correctly scores zero, so blanks and wrong answers cost the same. They only differ if you set a wrong-answer penalty, which is applied to the number of wrong answers.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/test-score/curl
curl "https://calculator.free/api/v1/test-score/?mode=correct&correct=18&total=20"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/test-score/?" + new URLSearchParams({
"mode": "correct",
"correct": "18",
"total": "20"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.