EZ Grader

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Walk-through

How to Use This Calculator

3 steps

1

Enter the total number of questions

Type how many questions or items the test has (or tap a preset — 10, 20, 25, 50, 100). This is the denominator for every percentage the grader produces.

2

Enter how many were missed

Enter the number wrong — or switch the toggle to enter the number right instead. The score, letter grade, and grading scale update instantly with each keystroke.

3

Read the grade and the full scale

The result card shows the percentage, the letter grade, and how many more correct answers reach the next grade up. Open the Full Scale Table tab for the complete "# wrong → %" chart, then copy, print, or download it.

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Reference

Formula & Methodology

3 formulas

Percentage score

score% = (total − wrong) / total × 100

The fraction of questions answered correctly, expressed as a percentage. Equivalent to (correct / total) × 100. Example: 17 correct out of 20 = 17 / 20 × 100 = 85%.

Points-based score

score% = earned / possible × 100

Used when questions are weighted or when partial/half-point credit is allowed. Example: 42.5 points earned out of 50 possible = 42.5 / 50 × 100 = 85%.

Letter grade

letter = first band where score% ≥ cutoff

The percentage is mapped to a letter using the grading scale. With the default scale, 90+ = A, 80–89 = B, 70–79 = C, 60–69 = D, below 60 = F. Cutoffs are editable, so a stricter or lighter scale changes the letter without changing the percentage.

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Glossary

Key Terms Explained

6 terms

Total questions The number of items on the test — the denominator of the percentage. A larger total means each wrong answer costs fewer percentage points (one miss on 100 questions is −1%, but on 10 questions it is −10%).

Number wrong How many questions were answered incorrectly (or left blank). Subtracted from the total to get the number correct. The toggle lets you enter the number right instead — the grader converts between them.

Percentage score Correct answers as a share of the total, from 0% to 100%. This is the raw, uncurved score before any letter grade is applied.

Letter grade A letter (A–F) assigned by comparing the percentage to a set of cutoffs. The cutoffs are a policy choice, not a fact — different schools use different scales.

Grading scale The table of percentage cutoffs that maps a score to a letter. The default A 90 / B 80 / C 70 / D 60 scale is the most common in U.S. schools, but it is fully editable here.

Curve An adjustment that raises scores after grading — for example, adding points so the top score becomes 100%, or lowering cutoffs. The EZ Grader reports the straight, uncurved percentage; apply a curve by editing the scale cutoffs.

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Scenarios

Real-World Examples

3 worked examples

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Quiz of 20

Student missed 3 on a 20-question quiz

Total questions 20 Number wrong 3

17 correct out of 20 = 85%, a B on the default scale. Just one more correct answer (18/20 = 90%) would have earned an A — useful feedback for a student who is right on a grade boundary.

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Big exam

100-question exam, 12 wrong

Total questions 100 Number wrong 12

88 of 100 = 88%, a B. On a 100-item test each question is worth exactly 1%, so the percentage equals the number correct. The full scale table makes it easy to read every possible score at a glance while grading a stack of papers.

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Weighted test

Partial credit, 42.5 of 50 points

Points earned 42.5 Points possible 50

Using the Points-Based tab, 42.5 / 50 = 85%, a B. Points mode is the right choice when questions carry different weights or when half-point partial credit is awarded, because a simple count of right vs. wrong cannot capture fractional credit.

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Deep Dive

How to grade a test fast — and what the letter actually means

3 chapters · 4 min read

The EZ Grader turns a count of wrong answers into a percentage and a letter grade in one step, then prints the full "# wrong → %" scale teachers have used on paper grading wheels for decades. This guide covers the simple math behind it, how letter-grade scales differ, and when to reach for points-based grading or a curve.

The math behind the grade

Percentage grading is one division: subtract the number wrong from the total, divide by the total, and multiply by 100. On a 20-question quiz, three wrong leaves 17 correct, and 17 ÷ 20 × 100 = 85%.

The size of the test changes how much each question is worth. On a 10-question quiz, one wrong answer drops the score a full 10 points; on a 50-question test the same miss costs only 2 points. That is why the full scale table is so useful — it shows the exact value of every possible number wrong for the test in front of you.

Percentage-to-letter scales

The most common U.S. scale is the 10-point scale: 90+ is an A, 80–89 a B, 70–79 a C, 60–69 a D, and below 60 an F. Many schools add plus/minus bands (an 88 becomes a B+), and some use a stricter 7-point scale where an A starts at 93. None of these are universal — the cutoffs are a grading-policy decision.

Because the cutoffs are editable in this tool, you can match your own syllabus exactly. Changing a cutoff never changes the percentage; it only changes which letter the same percentage earns.

Points-based grading and curving

When questions are weighted differently, or when you award partial or half-point credit, a simple right/wrong count is not enough. The Points-Based tab divides points earned by points possible, so a 42.5-out-of-50 result lands at 85% even though no whole number of "questions" was missed.

Curving is a separate, optional step applied after grading — for instance, adding a fixed number of points to every score, or lowering the cutoffs so more students clear each band. The EZ Grader reports the straight, uncurved percentage; to apply a cutoff-style curve, simply lower the A/B/C/D thresholds in the editable scale.

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Questions

Frequently Asked Questions

8 questions

How do I calculate a test grade by hand?+

Subtract the number of wrong answers from the total number of questions to get the number correct, divide that by the total, and multiply by 100. For example, 17 correct out of 20 is 17 ÷ 20 = 0.85, or 85%. The EZ Grader does this instantly and also assigns the letter grade.

What is the standard grading scale?+

The most common U.S. scale is the 10-point scale: 90–100% = A, 80–89% = B, 70–79% = C, 60–69% = D, and below 60% = F. Some schools use plus/minus variants or a stricter scale where an A starts at 93%. You can edit the A/B/C/D cutoffs in this calculator to match your school's policy.

Can I enter the number right instead of the number wrong?+

Yes. Use the toggle above the input to switch between entering the number wrong and the number right. The grader converts between them automatically and keeps the same underlying score, so the result does not change when you switch modes.

How do I grade a test with partial credit or weighted questions?+

Use the Points-Based tab. Enter the total points the student earned and the total points possible, and the grader divides them for the percentage. This handles half-point credit (the input accepts decimals) and questions that are worth different amounts.

Does the EZ Grader apply a curve?+

No — it reports the straight, uncurved percentage. If you want to curve grades by adjusting the cutoffs (a common approach), lower the A/B/C/D thresholds in the editable scale and the letter grades update accordingly. The percentage itself stays the same.

Why does one wrong answer affect a short test more?+

Each question is worth (100 ÷ total) percent. On a 10-question quiz that is 10 points per question, so one miss drops the score to 90%. On a 100-question exam each question is worth 1%, so one miss only drops the score to 99%. The full scale table shows the exact value of every wrong answer for your test size.

Can I share or print the grading scale?+

Yes. The calculator encodes your inputs into the page URL, so copying the link with the Share button reproduces the exact scenario. The CSV button downloads the score breakdown, and Print produces a clean copy of the full grading scale table.

Does the Points-Based tab support plus/minus grades?+

Yes. Open "Edit grading scale" on the Points-Based tab and check "Use +/- grades" to split each letter band into a minus, plain, and plus sub-grade (for example B- / B / B+). The width of each sub-band is adjustable — 3 percentage points by default. This scale is independent from the Quick Grade tab's scale, so you can run a stricter or looser cutoff for weighted, partial-credit grading than for simple right/wrong counts.

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