Test grade calculator
Enter the points earned and the points possible: 85 out of 100 comes back as 85 % and a B on the standard ten-point US scale. A score above the maximum is refused, so a typo never looks like extra credit. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Score
- 85
- Maximum
- 100
- Percentage
- 85
- Letter grade
- B
A raw test score only becomes a letter grade after you divide by the maximum possible points and apply a published percentage scale. Teachers, students, LMS plugins, and homework checkers all need the same conversion: percentage equals score divided by maximum times one hundred, then a letter from the standard ten-point United States thresholds. This test grade calculator accepts a finite raw score and a positive maximum, returns the percentage together with the letter grade A through F, and rejects a negative score or a score that exceeds the maximum so a typing error never looks like extra credit.
What a test letter grade is and why the ten-point scale is the default
A test letter grade is not the raw point total printed on the last page of a packet. It is the ratio of points earned to points possible, scaled to a percentage, then mapped through a published threshold table onto the letters A, B, C, D, and F.
The standard ten-point United States scale used here is simple on purpose: ninety percent and above is an A, eighty percent up to but not including ninety is a B, seventy percent up to eighty is a C, sixty percent up to seventy is a D, and anything below sixty percent is an F.
That scale is what students mean when they search for a test grade calculator, what many K–12 report cards still print, and what learning-management plugins need when they convert a quiz of forty-two out of fifty into a letter without inventing a curve. Equal treatment of every point on the same instrument is the whole point of the conversion: unlike a weighted course grade, there are no syllabus categories, no category weights, and no dropped lowest quiz. Percentage equals score divided by maximum times one hundred.
A score of eighty-five on a one-hundred-point exam is eighty-five percent, letter B. A score of forty-five on a fifty-point quiz is ninety percent, letter A — the same letter you would assign if the quiz had been scaled to one hundred first. Zero earned points on a positive maximum is a legitimate F, not an error.
Extra credit that pushes the raw score above the published maximum is not guessed here: the contract rejects a score that exceeds the maximum so a transposed digit cannot silently become an A.
Input contract, formula, rounding, and error behaviour
Optional decimals is an integer from zero to six that controls half-up rounding of the returned percentage; the default is two decimal places so a result such as eighty-seven point five matches common gradebook displays. The letter grade is assigned from that rounded percentage so the number you show and the letter you show cannot disagree: eighty-nine point nine nine five at two decimals becomes ninety point zero zero, letter A.
A maximum that is zero or negative also fails, because dividing by a non-positive ceiling is not a test percentage. A negative score fails. Example: score eighty-five and maximum one hundred yields percentage eighty-five and letter B.
Example: score forty-five and maximum fifty yields percentage ninety and letter A. Failed validation is not billed.
What you can do with it
Quiz and exam letter from raw points
Students enter points earned and points possible to see the percentage and the standard A–F letter before the teacher posts the gradebook.
Stack of papers, one conversion each
Instructors send each raw score with the published maximum to append a verified percentage and letter column and catch totals typed above the ceiling.
LMS and homework-checker automation
Plugins map stored points earned and points possible onto score and maximum so the letter matches the ten-point scale used on the landing.
FAQ
How is the test letter grade calculated?
Percentage = score / maximum × 100, then a letter from the standard ten-point scale: A ≥ 90, B ≥ 80, C ≥ 70, D ≥ 60, F below 60. The letter uses the rounded percentage so the displayed percent and the letter always agree.
What happens if the score exceeds the maximum?
A score above the published maximum is rejected and is not billed, so extra credit above the ceiling cannot look like a successful A.
Can the score be zero? Can it be negative?
Zero earned points on a positive maximum is a valid F at 0%.
Does this compute a weighted course grade or GPA?
No. This landing converts one raw score and one maximum into a percentage and a letter. Weighted syllabus categories and GPA points are different searches.
What letter grade is 45 out of 50?
An A. Forty-five divided by fifty is 90 %, exactly the A threshold, the same letter a 90 out of 100 would get. Because the score is divided by the real maximum, you never have to rescale the quiz to 100 first.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/edu/test-grade \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"score":85,"maximum":100}'const res = await fetch("https://api.kit.forhosting.com/edu/test-grade", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"score": 85,
"maximum": 100
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/edu/test-grade",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"score": 85,
"maximum": 100
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/edu/test-grade", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"score":85,"maximum":100}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"score":85,"maximum":100}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/edu/test-grade", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"score": 85,
"maximum": 100
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "edu.test_grade",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
The arithmetic is fully deterministic, runs free in your browser, and is available over the API at $0.002 per successful request with no language model and no gradebook service on the hot path.
Input contract, formula, rounding, and error behaviour
POST a JSON body with two required finite numbers: score, the points earned, and maximum, the points possible. Each field may arrive as a JSON number or as a numeric string. Score also accepts the aliases earned, points, raw, and raw_score; maximum accepts max, max_score, total, and out_of so scripts that already speak in those terms do not need a rename step. Missing fields, empty strings, and non-finite values fail with invalid_input naming the problem. A score that exceeds the maximum fails with invalid_input so extra credit above the published ceiling never looks like a successful A. On success the body echoes score and maximum, returns percentage, returns letter_grade as one of A, B, C, D, or F, and restates the identity in the formula field. Pair the structured JSON with your own report card if you need plus-minus cutoffs or a curve; this endpoint returns the standard ten-point letter only.
Where a test-grade letter API earns its keep
Classrooms and tutoring platforms use a test grade calculator so learners can convert tonight’s quiz into a letter without mixing up the maximum or applying a syllabus weight that does not belong on a single instrument. Exam generators and homework checkers need a deterministic oracle that rejects a negative score and a score that exceeds the maximum instead of taking absolute values and marking swapped numbers as an A. Learning-management plugins that already store points earned and points possible can map those two fields onto score and maximum and obtain a letter without standing up a gradebook database. Teachers and teaching assistants batch-call the API per paper to append a verified percentage and letter column when exporting a stack of raw scores, catching rows where a score was typed above the published total. Keep requests small, pin the rounded percentage and letter_grade in tests, and you get reproducible test letters for homework, edge workers, and gradebook scripts without inventing a curve, a plus-minus table, or a weighted course average on the same landing.
Technical questions
What does the test grade calculator cost?
The browser tool is free. API requests use prepaid balance at $0.002 per successful call; invalid input is not billed.