Percent Change Calculator
Percent Change Calculator
Enter an old value and a new value to find the percentage change between them — automatically detecting whether it's an increase or a decrease.
The result is always shown as a positive percentage paired with a clear "increase" or "decrease" label, rather than relying on a confusing negative sign to indicate direction — going from 50 to 75 is a 50% increase, calculated as the 25-unit change divided by the original 50 value. This is the calculator to reach for whenever comparing two values over time — a stock price, a website's traffic, a company's revenue — since percent change puts the size of the movement in proportional, comparable terms rather than just the raw difference.
- Formula: Percent Change = |(New Value − Old Value) ÷ Old Value| × 100.
- Example: from 50 to 75 = (25 ÷ 50) × 100 = 50% increase.
- Direction: the result is always shown as a positive percentage, with a separate "increase" or "decrease" label so it's unambiguous either way.
What if the old value is zero?
Percent change is undefined when starting from zero (any increase from zero is technically an infinite percentage), so this calculator returns 0% in that edge case rather than an error.
Is this the same as percent difference?
Not quite — percent change measures change relative to the starting (old) value specifically, while percent difference (less common) sometimes uses the average of the two values instead.
Percent Change Calculator
Enter an old value and a new value to find the percentage change between them — automatically detecting whether it's an increase or a decrease.
The result is always shown as a positive percentage paired with a clear "increase" or "decrease" label, rather than relying on a confusing negative sign to indicate direction — going from 50 to 75 is a 50% increase, calculated as the 25-unit change divided by the original 50 value. This is the calculator to reach for whenever comparing two values over time — a stock price, a website's traffic, a company's revenue — since percent change puts the size of the movement in proportional, comparable terms rather than just the raw difference.
- Formula: Percent Change = |(New Value − Old Value) ÷ Old Value| × 100.
- Example: from 50 to 75 = (25 ÷ 50) × 100 = 50% increase.
- Direction: the result is always shown as a positive percentage, with a separate "increase" or "decrease" label so it's unambiguous either way.
What if the old value is zero?
Percent change is undefined when starting from zero (any increase from zero is technically an infinite percentage), so this calculator returns 0% in that edge case rather than an error.
Is this the same as percent difference?
Not quite — percent change measures change relative to the starting (old) value specifically, while percent difference (less common) sometimes uses the average of the two values instead.