Convert marks into a percentage, or work out how many marks you need to hit a target grade.
Grading scales vary significantly from country to country and even between institutions. For grade boundary reference tables, choose your education system below.
To turn marks into a percentage, divide the marks you achieved by the total marks available and multiply by 100. To work the other way — finding out how many marks you need for a target grade — multiply the target percentage by the total marks and round up.
The formula is: percentage = (marks achieved ÷ total marks) × 100. For example, if you scored 68 out of 80, that's (68 ÷ 80) × 100 = 85%. The calculator above does this instantly as you type, and rounds to two decimal places where the result isn't a whole number.
If you know the percentage you need but not the marks, use the "Percentage → Marks needed" mode. It multiplies your target percentage by the total marks available, then rounds up to the next whole mark — since most exams and assignments don't award fractional marks, you need to clear the rounded figure, not just the exact decimal.
A percentage score doesn't always map to the same grade — boundaries depend on the qualification, subject, exam board, and even the year, as boundaries are often adjusted after each exam series to account for difficulty. For approximate reference tables, see the UK GCSE & A-Level boundaries or the US letter grade & GPA scale.