Work out what percentage one number is of another, increase or decrease a number by a percentage, find the percentage change between an old and a new value, or compare two values with percentage difference.
🔢 Basic Percentage Calculator
Calculate what percentage one number is of another
📈 Percentage Increase Calculator
Calculate the new value after a percentage increase
📉 Percentage Decrease Calculator
Calculate the new value after a percentage decrease
⚖️ Percentage Difference Calculator
Calculate the percentage difference between two values
📖 About Percentage Difference
- Used to compare two values without a clear starting point
- Always expressed as a positive percentage
- Different from percentage change (which has a reference value)
🔄 Percentage Change Calculator
Calculate percentage change from old to new value
📖 Understanding Percentage Change
- Positive: Indicates an increase from old to new value
- Negative: Indicates a decrease from old to new value
- Zero: No change between old and new value
🎯 What Percent Of Calculator
Find what number is a certain percentage of another number
What this percentage calculator does
- Basic %: what percentage a value is of a total, with the decimal and simplified fraction.
- % Increase: a number increased by a percentage.
- % Decrease: a number reduced by a percentage.
- % Difference: how far apart two values are, relative to their average.
- % Change: the percentage rise or fall from an old value to a new value.
- What % of: a given percentage of a number, such as 15% of 200.
The formulas
| Calculation | Formula |
|---|---|
| Percentage of a total | value ÷ total × 100 |
| Increase by p% | original × (1 + p ÷ 100) |
| Decrease by p% | original × (1 − p ÷ 100) |
| Percentage change | (new − old) ÷ old × 100 |
| Percentage difference | |a − b| ÷ ((a + b) ÷ 2) × 100 |
Worked examples: 15% of 200 is 30. 200 increased by 25% is 250, and decreased by 25% is 150. Going from 50 to 75 is a 50% increase. The percentage difference between 50 and 150 is 100%, because they differ by 100 and their average is 100.
Things to keep in mind
Percentage change and percentage difference are not the same: change compares to the old value, while difference compares to the average of the two. Percentage change is undefined when the old value is 0, and percentage difference is undefined when the two values average to 0.
Frequently asked questions
How do I calculate a percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100.
Why is a 50% increase followed by a 50% decrease not back to the start?
Because the second percentage applies to the larger number. 100 up 50% is 150, and 150 down 50% is 75.
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