Numbers
Percentage Change Calculator
Used by developers, writers, and creators worldwide.
A percentage change calculator tells you how much a value has gone up or down in percentage terms between an original and a new figure. Enter the starting value and the ending value, and it returns the absolute change in raw units plus the percentage increase or decrease, clearly labelled with the direction. This is the calculation behind price changes, salary raises, investment returns, traffic growth, and any before-and-after comparison. Analysts use it to summarise results, shoppers to judge a discount or markup, and students to check percentage homework. Getting the base right is where people slip up — the percentage is always measured against the original value, not the new one — and the tool handles that correctly, including the case where the original value is zero. Use it to express any change as a clean percentage that is easy to compare across different starting amounts.
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How to use
- Choose your options above
- Click Generate
- Copy your result
Detailed instructions
- Enter the original value.
- Enter the new value.
- Click Generate to see the change.
- Read the absolute and percentage difference.
Use Cases
- •Measuring a price increase or a discount
- •Calculating a percentage salary raise
- •Summarising investment or revenue growth
- •Comparing before-and-after metrics
- •Checking percentage change homework
Tips
- →The percentage is always relative to the original value.
- →A positive result is a rise, a negative one is a fall.
- →Use it to compare changes that started from different bases.
- →Watch the zero-base case where the percentage is undefined.
FAQ
which value is the percentage measured against
Always the original value. Percentage change equals the difference divided by the original, times 100. Measuring against the new value instead is the most common mistake and gives a different, incorrect figure.
what happens if the original value is zero
Percentage change is mathematically undefined when the starting value is zero, because you would be dividing by zero. The tool flags this and still shows the absolute change so the comparison is not lost.
how are increases and decreases shown
A positive result is an increase and a negative result is a decrease, and the tool labels each explicitly and adds a sign. This removes any ambiguity about direction when you read or share the result.
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