Percentage Change Calculator
Enter an old value and a new value to see the percentage change.
This calculator finds the percentage change between an old value and a new value. Enter both numbers and it shows the percentage increase or decrease, whether the value rose or fell, and the plain difference. Everything runs in your browser, so nothing you type leaves your device.
How to use
- Enter the old value (the starting number) in the first field.
- Enter the new value (the ending number) in the second field.
- Read the percentage change, the direction (increase or decrease), and the difference.
- Use Swap to flip the two values, or Copy result to grab the percentage.
Examples
- Old value 200, new value 250: a 25% increase, difference of 50.
- Old value 80, new value 60: a 25% decrease, difference of -20.
- Old value 1,000, new value 1,500: a 50% increase, difference of 500.
FAQs
- How is percentage change calculated?
- It is the new value minus the old value, divided by the absolute value of the old value, then multiplied by 100. For example, going from 200 to 250 gives (250 minus 200) divided by 200, times 100, which is 25%.
- Why can the old value not be zero?
- Percentage change measures growth relative to the starting amount. Dividing by zero is undefined, so a change from zero has no meaningful percentage. The calculator flags this instead of returning a broken number.
- What is the difference between percentage change and percentage difference?
- Percentage change has a clear starting point (the old value) and an ending point (the new value), so direction matters. Percentage difference compares two values without one being the baseline and is usually computed against their average.
- How does it handle negative numbers?
- It divides by the absolute value of the old value, so the sign of the result reflects the real direction. Moving from -10 to -5 is a rise, so it reports a positive 50% increase.
- Can I use it to find a percentage decrease?
- Yes. If the new value is smaller than the old value, the result is negative and the direction reads as a decrease. For example, 80 down to 60 is a 25% decrease.
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