Percentage grading scores work by how many points were earned out of the points possible. Rubric grading scores work against written criteria, with a level such as 1 to 4 for each one. Percentages are quick and easy to compare, while rubrics show exactly where a piece of work was strong or weak. Many schools use both: a rubric to judge the work, and a percentage to record it.

Whichever method is used, the result usually ends up as a letter. For how those letters are decided, see the main grading scales guide.

What percentage grading is

In percentage grading, each assignment has a points total, and the score is points earned divided by points possible. The percentage is then matched to a letter on the school’s scale. It is the method most people think of first, and the one our guide on the percentage grade formula explains step by step.

The strength of a percentage is that it is simple and comparable: 85% means the same arithmetic in every class. The weakness is that a single number hides detail. Two students can both score 80% on an essay for very different reasons, and the number does not say which skills need work.

What rubric grading is

A rubric lists the criteria a piece of work will be judged on, such as ideas, organisation, evidence and language. For each criterion it describes what each level looks like, usually on a scale of 1 to 4, where 4 is the strongest. The teacher picks a level for each row and the levels are combined into an overall result.

The strength of a rubric is that the expectations are clear before the work starts, and the feedback is specific afterwards. The weakness is that levels are broad. A jump from 3 to 4 is a big step, and two teachers may place the same work at different levels unless they have agreed what each level means.

Pros and cons side by side

Converting rubric scores to a percentage

To turn a rubric result into a percentage, add the levels earned and divide by the most they could have earned. A student who scores 4, 3, 3 and 2 on four criteria has 12 points out of 16. That is 12 ÷ 16 × 100 = 75%. If you only have one criterion, the rule is the same: 3 out of 4 is 75%. The percentage calculator will do the division for you.

On a 1 to 4 scale, each level converts like this: 4 is 100%, 3 is 75%, 2 is 50% and 1 is 25%. Notice that the lowest level is 25%, not 0%. A student who shows only the beginning of a skill still gets a quarter of the marks. Some schools adjust the mapping, for example by treating a 3 as a B-range score, so check which conversion your school uses.

Once you have the percentage, you can change it into a letter. Our letter grade calculator does that. As an example, 75% is a C on the 10-point scale, a C on the plus/minus scale and a D on the 7-point scale, so the scale matters as much as the score.

Weighted rubric criteria

Not every criterion has to count equally. A teacher might give ideas 40% of the mark and the other three criteria 20% each. Each criterion is turned into a fraction of its level out of 4, multiplied by its weight, and added up.

With the same scores of 4, 3, 3 and 2: ideas is 4/4 × 40 = 40, organisation is 3/4 × 20 = 15, evidence is 3/4 × 20 = 15 and language is 2/4 × 20 = 10. The total is 80%, which is higher than the 75% from equal weights, because the student did best on the criterion that counts most. That is a B on the 10-point scale, a B- on the plus/minus scale and a C on the 7-point scale.

When each method fits

• Use percentages when answers are clearly right or wrong, such as maths tests, spelling quizzes and short homework.
• Use a rubric when quality matters more than a count, such as essays, presentations, lab reports and creative projects.
• Use both when the gradebook needs a number but the students need detailed feedback: mark with a rubric, then convert the total to a percentage.

Whichever method you choose, share it before the work starts. If you grade for a living, our teacher grading tips cover how to keep marking quick and fair.

Frequently asked questions