Percentage Change Calculator
A percentage change calculator shows how much a number grew or shrank as a percent of where it started. Enter an old and a new value to get the percent increase or decrease, or enter a number and a percent to raise or lower it, with the multiplier and the percent that would undo the change.
Positive means an increase; negative means a decrease
Percentage Change Formulas
One formula measures a change. Two more apply a change. All three compare against the starting value.
Percent Change
"A price went from $50 to $65."
Increase by a Percent
"Raise $80 by 25%."
Decrease by a Percent
"Take 25% off $60."
How to Use the Percentage Change Calculator
Measure or apply a change in 4 steps.
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Pick a Mode
% change from A to B measures a change. Increase and Decrease apply one.
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Type the Two Numbers
Old value first, then the new value or the percent.
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Read the Result
The badge says whether it is an increase or a decrease. Press Enter or Calculate any time.
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Check the Extras
The change as an amount, the multiplier, and the percent that would take you back to the start.
Why +20% Then −20% Isn't Zero
The second percent is taken from a different number, so equal-sized ups and downs don't cancel.
Multipliers and How to Undo Them
Multiply by the multiplier to apply a change. The last column is the change that takes you back to the start.
| Change | Multiply by | To undo it |
|---|---|---|
| +5% | 1.05 | −4.76% |
| +10% | 1.1 | −9.09% |
| +25% | 1.25 | −20% |
| +50% | 1.5 | −33.33% |
| +100% | 2 | −50% |
| −10% | 0.9 | +11.11% |
| −20% | 0.8 | +25% |
| −25% | 0.75 | +33.33% |
| −50% | 0.5 | +100% |
Percentage Change on a 4 Function Calculator
A basic calculator works one step at a time, so do the subtraction first.
50 → 65
Increase 80 by 25%
Decrease 60 by 25%
Percentage Change Examples
Prices, pay, scores and savings all change by percents.
Price Rise
Gas goes from $3.20 to $3.60 a gallon.
Pay Raise
A $52,000 salary gets a 4% raise.
Test Score Improvement
A score goes from 68 to 85.
Website Visitors
Monthly visitors fall from 12,000 to 9,000.
Savings Growth
An account grows from $1,500 to $1,800.
Read Percent Change vs Percentage Points to avoid the most common percent mix-up, or start with How to Calculate a Percentage.
Explore Other Calculators
Frequently Asked Questions
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. From 50 to 65: (65 − 50) ÷ 50 × 100 = 30%, a 30% increase.
How do I increase a number by a percentage?
Multiply the number by 1 plus the percent as a decimal. To increase 80 by 25%, multiply 80 × 1.25 = 100.
How do I decrease a number by a percentage?
Multiply the number by 1 minus the percent as a decimal. To decrease 60 by 25%, multiply 60 × 0.75 = 45.
Why doesn't a 20% decrease undo a 20% increase?
Because the second percent is taken from a different number. 100 increased by 20% is 120, and 20% of 120 is 24, so decreasing 120 by 20% gives 96. To get back to 100 you need a 16.67% decrease.
Can percentage change be more than 100%?
Yes, for increases. Going from 40 to 100 is a 150% increase. A decrease can never be more than 100%, because a 100% decrease already brings a positive number to zero.
What if the old value is zero?
Percentage change is undefined when the old value is 0, because the formula divides by the old value. Describe the change as an amount instead, for example "up from 0 to 12".