Percentage Change Calculator
Find the percentage increase or decrease between an old value and a new value, useful for tracking price changes, salary raises, weight loss, or business growth.
About this percentage change calculator
Whenever something changes from one number to another, a price, a salary, a population, the percentage change tells you how big that shift really was, which raw numbers alone do not always make clear.
How percentage change calculator works
The formula is: Percentage Change = ((New Value − Old Value) ÷ Old Value) × 100. For example, going from 200 to 250 is ((250 − 200) ÷ 200) × 100 = 25% increase.
Common uses
- Tracking how much a price has risen or dropped
- Measuring a salary increase in percentage terms
- Comparing year-over-year business growth
- Calculating percentage weight loss or gain
How to use this tool
- Enter the old value.
- Enter the new value.
- See the percentage increase or decrease instantly.
What to know before using it
A negative result means a decrease. If the old value is zero, percentage change cannot be calculated, since you cannot divide by zero.
Privacy and browser-first processing
This tool runs entirely in your browser using JavaScript. Nothing you enter is uploaded or stored.
Frequently asked questions
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, then multiply by 100: ((New − Old) ÷ Old) × 100.
What does a negative percentage change mean?
It means the value decreased. For example, a result of −10% means the new value is 10% lower than the old value.