Grade a Stack of Tests in Minutes
Marking 30 papers with 27 questions each means 30 rounds of the same mental math. This test grade calculator removes all of it: set the number of questions once, and the full chart shows the percentage and letter grade for every possible number of wrong answers. As you mark each paper, tap the + stepper per mistake and read off the grade — the matching chart row highlights automatically.
It is the digital version of the slide-style "EZ grader" chart, with two upgrades: it handles up to 500 questions, and it shows one decimal place — on a 10-question quiz the difference between 89% and 90% is a full letter grade, so the precision matters.
The Math Behind the Grade
The score is simply correct answers divided by total questions: (total − wrong) ÷ total × 100. Letter grades then follow the standard US scale — 90% and above is an A range, 80s are Bs, 70s are Cs, 60s are Ds, and anything below 60% is an F, with plus/minus bands at roughly three-point intervals. Schools vary (some draw the A line at 94%, some skip plus/minus), so the exact scale is printed under the chart for easy adjustment.
Tips for Faster Grading
- Sort before you grade: mark all papers question-by-question rather than paper-by-paper — errors are easier to spot when you see the same answer thirty times.
- Count wrong, not right: on a good class set there are far fewer mistakes than correct answers, and this calculator is built around exactly that count.
- Print the chart: the grading chart for your question count is a clean table — screenshot it for grading offline or share it with a co-teacher.
- Partial credit? Convert to half-questions: a 20-question test with half-point deductions is a 40-question test in the calculator.
Quick Grading Charts for Common Test Sizes
The three most common quiz lengths, condensed to the rows where the letter grade changes — scan down to the number wrong and read the grade. For any other size, set the question count in the calculator above and get the full chart.
