Percentage Change Calculator
Percentage change tells you how much a number has grown or shrunk relative to where it started. It is how prices, populations, grades and investment returns are compared. Enter the old and new values and this calculator gives the percent change, the absolute difference and the percentage you would need to reverse the change.
How to use the percentage change calculator
- Enter the starting (old) value and the ending (new) value.
- Read the percent change. A plus sign means an increase and a minus sign a decrease.
- Check the last row to see why going back down is not the same percentage as going up.
Formula
Percent change = (new − old) ÷ |old| × 100. To go back from the new value to the old one, the change needed is (old − new) ÷ |new| × 100, which is a different percentage because the base is different.
Worked examples
A price rise
A subscription goes from $50 to $65. (65 − 50) ÷ 50 × 100 = +30%.
A price drop
A stock falls from $80 to $60. (60 − 80) ÷ 80 × 100 = −25%. To recover to $80 it would need to rise by 33.3%.
Percent change in practice
Why up and down are not symmetric
A 50% rise on 100 gives 150, but a 50% fall on 150 gives 75. To undo a rise of p you need a fall of p ÷ (1 + p). This is why an investment that loses 50% needs a 100% gain to recover.
| Fall | Gain needed to recover |
|---|---|
| 10% | 11.1% |
| 25% | 33.3% |
| 50% | 100% |
| 75% | 300% |
Percent change or percentage points?
If unemployment moves from 5% to 6%, it rose 1 percentage point and 20 percent. Headlines often mix the two, so check which is meant.
Chaining changes
Successive changes multiply. A price up 10% then up 10% is ×1.1 × 1.1 = 1.21, a 21% rise, not 20%. To find the average yearly rate over several years use the geometric mean, not the simple average.
Everyday uses
Comparing salaries, tracking prices over time, measuring a business’s growth and reading test-score improvements all use percent change. For discounts see the discount calculator.
Practice problems
Try these yourself first, then check your answer. The answers come from the calculator above.
- A rent rises from $1,200 to $1,320. What is the percent increase?
Show answer
Percent change: +10%
- A stock drops from $45 to $36. What is the percent change?
Show answer
Percent change: -20%
Common mistakes to avoid
- Dividing by the new value instead of the old one.
- Treating a rise of 30% followed by a fall of 30% as break-even. 100 becomes 130 then 91.
- Confusing percent change with percentage points. A rate moving from 4% to 5% rose 1 percentage point, or 25%.
Frequently asked questions
How do I calculate percent increase?
Subtract the old value from the new value, divide by the old value and multiply by 100.
Why is going up 50% and then down 50% not break-even?
The second percentage applies to a bigger number. 100 → 150 → 75.
What if the old value is zero?
Percent change is undefined because you cannot divide by zero.
How is this different from the percentage calculator?
The percentage calculator covers five kinds of question. This tool focuses on change and its reversal.
Reviewed September 26, 2026 by the SolveCalcPro editorial team. Found a mistake? Tell us; see our editorial policy.