Marks Calc

Percentage Change Calculator

Quickly determine the exact percentage change — increase or decrease — between any two numbers. Essential for tracking grade improvements, financial growth, and data trends.

How It Works

Percent Change = ((New − Old) / |Old|) × 100

Subtract the old value from the new value, then divide the result by the absolute value of the old value, and multiply by 100. A positive result indicates an increase; a negative result indicates a decrease.

Quick Tips

Sign Matters
A negative result means the value decreased. A positive means it increased.
Baseline
The "Old" value is always your reference. Swapping old and new gives a different answer.
Grade Growth
Use this to measure how much your score improved from one test to the next.
Over 100%
A percentage change can exceed 100% — going from 5 to 15 is a 200% increase.

Step-by-Step Instructions

  1. 1Enter the original (old) value — for example, your previous exam score.
  2. 2Enter the new value — for example, your latest exam score.
  3. 3The calculator instantly shows the percentage change and whether it is an increase or decrease.

How Percentage Change Works

Percentage change is one of the most useful mathematical concepts for everyday life. Whether comparing test scores, salary figures, or stock prices, the formula is always: divide the difference by the original value and multiply by 100.

The Formula
Change =
New Value \u2212 Old Value
|Old Value|
\u00d7 100
Worked Example

Exam score improved from 65 to 80:

Change = (80 \u2212 65) / 65 \u00d7 100
Change = 15 / 65 \u00d7 100 = +23.1%

A positive result \u2014 the score improved by 23.1%.

Frequently Asked Questions

What is percentage change?▼
Percentage change measures how much a value has changed relative to its original amount, expressed as a percentage. It shows the direction (increase or decrease) and the magnitude of the change.
How is percentage change different from percentage difference?▼
Percentage change compares a new value to an old baseline (time-based). Percentage difference compares two values of the same type with no defined starting point, using their average as the base.
Can I get a negative percentage change?▼
Yes. If the new value is less than the old value, the result will be negative, indicating a percentage decrease.

Related Tools

Percentage Increase
Calculate % increase specifically.
Percentage Difference
Compare two values without a baseline.