How to Calculate Percentage Increase or Decrease in Your Marks

Quick answer: percentage change = (new mark − old mark) ÷ old mark × 100. If your marks went from 60 to 72, that is a 20% increase. If they fell from 80 to 68, that is a 15% decrease.

Students, parents and teachers often say a result “went up by 12%” when they really mean 12 percentage points. The two are different, and mixing them up can make progress look bigger or smaller than it is. This guide explains both, with worked examples and a quick reference table.

The formula

• Change = New mark − Old mark
• Percentage change = Change ÷ Old mark × 100

A positive answer is an increase. A negative answer is a decrease. Always divide by the old mark, because you are measuring change from where you started.

Example 1: percentage increase

Your maths test score went from 60 to 72 (both out of 100).

1. Change: 72 − 60 = 12
2. Percentage change: 12 ÷ 60 × 100 = 20% increase

Example 2: percentage decrease

Your physics score fell from 80 to 68.

1. Change: 68 − 80 = −12
2. Percentage change: −12 ÷ 80 × 100 = −15%, a 15% decrease

Notice that both examples have a change of 12 marks, but the percentage change is different because the starting marks are different.

Percentage points vs percent

When your marks are already percentages, there are two ways to describe the change:

• Percentage points: the simple difference. 60% to 72% is an increase of 12 percentage points.
• Percent (relative change): the change compared with where you started. 60% to 72% is a 20% increase.

Both are correct, but say which one you mean. Schools and report cards usually talk in percentage points.

Example 3: tests with different totals

If the tests have different maximum marks, convert each one to a percentage first.

1. Test 1: 45 out of 60 = 75%
2. Test 2: 70 out of 80 = 87.5%
3. Change in points: 87.5 − 75 = 12.5 percentage points
4. Relative change: 12.5 ÷ 75 × 100 = 16.7% increase

Need help with the first step? Use the Marks to Percentage Calculator or read how to calculate percentage of marks.

Quick reference table

Working backwards: what mark gives a 10% improvement?

Multiply your old mark by (1 + target ÷ 100). To improve 65 by 10%, you need 65 × 1.10 = 71.5. To find the mark after a decrease, multiply by (1 − decrease ÷ 100).

If you are planning ahead for an exam, the Final Grade Calculator tells you the score you need to reach a target overall grade.

Common mistakes

• Dividing by the new mark. From 60 to 72, 12 ÷ 72 gives 16.7%, which is wrong. Always divide by the starting value.
• Mixing points and percent. “Up 12%” and “up 12 points” are different statements when the mark is already a percentage.
• Comparing raw marks from tests with different totals. Convert to percentages first.
• Adding percentage changes. A 10% rise followed by a 10% fall does not bring you back to the start. 60 → 66 → 59.4.

FAQ

How do I calculate the percentage increase from one exam to the next?

Subtract the first score from the second, divide by the first score and multiply by 100.

Can the percentage increase be more than 100%?

Yes. Going from 20 to 50 is a 150% increase, because the change (30) is one and a half times the starting mark.

Is going from 40% to 50% a 10% increase?

It is a 10 percentage point increase, and a 25% relative increase (10 ÷ 40 × 100).

Is there a calculator for this?

Yes. The Percentage Calculator does the arithmetic for you, so you can check your answer in seconds.

Track your progress: record every test in the Student Study Planner & GPA Tracker to see your improvement across the semester.

Related guides

• How to Calculate Percentage of Marks (With Examples)
• How to Calculate Your Test Score Percentage (and What Grade It Is)
• What Percentage Is a B? Letter Grade to Percentage Chart

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