Loona EZ Grader — The Teacher's Slide-Scale, Digitised
Every teacher knows the moment: a 17-question quiz, a student with 4 wrong, and a mental-arithmetic pause. The paper EZ Grader wheel solved it for decades; this is the same idea, instant and with the whole chart visible.
Full grading chart for this test length
How to Use It
- Enter total questions on the test, quiz or assignment.
- Enter how many the student got wrong. The percentage and letter grade update as you type.
- Use the chart below to grade the whole class set quickly — your current row is highlighted; every other row is one lookup away.
How It Works
The grader computes correct = total − wrong, then percentage = correct ÷ total × 100 (one decimal place), and maps it to letters on the standard scale (A ≥ 90, B ≥ 80, C ≥ 70, D ≥ 60, F below 60). The chart simply runs the same calculation for every possible number wrong, so the highlighted row always matches the headline result.
Frequently Asked Questions
Which letter scale does it use?
The widely used US scale: A 90–100, B 80–89, C 70–79, D 60–69, F under 60. If your school uses different cut-offs, read the percentage (which is exact) and apply your own scale.
Does it round percentages?
To one decimal place, without rounding up to the next grade behind your back — 89.9% shows as 89.9%, a B. Your school's rounding policy is yours to apply.
Can I grade a whole class at once?
Use the chart: for a fixed test length, each student's grade is a single row lookup. For answer-key-based grading of a whole test, the Test Grader on this site marks question by question.