Math

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Percentage Change Calculator.

Calculate the relative change from an original value to a new value.

On-device calculationNo signup
01

Set your values

Results update as you type.

percentageChange: 25 %

percentageChange

0.000000%
difference: 20

difference

0.000000

Results update automatically as you type.

Use Cases

Track price changes

Determine the percentage increase or decrease in prices over time, helping you understand inflation or discounts.

Example: Original price: $50, New price: $40 → -20% change

Measure performance growth

Evaluate changes in metrics like sales, website traffic, or test scores to assess progress or decline.

Example: Original score: 80, New score: 92 → +15% change

Frequently Asked Questions

How do I calculate percentage change?
Enter the original value and the new value. The calculator computes the difference, divides by the original value, and multiplies by 100 to give you the percentage change. A positive result indicates an increase, while a negative result indicates a decrease.
What does a negative percentage change mean?
A negative percentage change means the new value is less than the original value, indicating a decrease. For example, if the original value is 100 and the new value is 80, the percentage change is -20%, representing a 20% decrease.
Can I use this calculator for any type of values?
Yes, you can use it for any numeric values, such as prices, quantities, measurements, or scores. Just ensure both values are numbers. The calculator works for both positive and negative numbers, but the original value should not be zero to avoid division by zero.

Tips & Common Mistakes

Tips

  • Ensure the original value is not zero, as percentage change is undefined in that case.
  • Double-check that you enter the correct values in the right fields: 'Original value' is the starting point, 'New value' is the final point.
  • Use the sign of the result to quickly interpret whether the change is an increase (positive) or decrease (negative).
  • For accurate comparisons, use consistent units for both values (e.g., both in dollars, both in kilograms).

Common Mistakes to Avoid

  • Swapping the original and new values, which reverses the sign and magnitude of the percentage change.
  • Using the new value as the denominator instead of the original value, leading to an incorrect percentage.
  • Entering zero as the original value, which causes a division by zero error and an undefined result.

Last updated: August 13, 2026