Percentage Change Calculator
Calculate the percentage increase or decrease between any two values — instantly and for free.
Tips: Use tab to move to the next field. Use shift-tab to move to the previous field. Press enter to calculate.
What is percentage change?
Percentage change measures how much a value has grown or shrunk relative to its starting point, expressed as a percentage. A positive result means an increase; a negative result means a decrease.
It is one of the most widely used calculations in everyday life — from comparing prices and tracking investment returns to measuring weight loss or monitoring business growth.
Percentage change formula
The formula for percentage change is:
A positive result indicates a percentage increase; a negative result indicates a percentage decrease.
How to calculate percentage change
- Subtract the old value from the new value to find the difference.
- Divide the difference by the old value.
- Multiply by 100 to convert to a percentage.
Example: A product cost $80 last month and costs $100 today. Difference = 100 − 80 = 20. Divided by old value: 20 ÷ 80 = 0.25. Multiplied by 100 = +25%.
Worked examples
| Scenario | Old value | New value | Change |
|---|---|---|---|
| Price increase | $80 | $100 | +25% |
| Salary cut | $60,000 | $54,000 | −10% |
| Weight loss | 90 kg | 81 kg | −10% |
| Revenue growth | $1,200,000 | $1,500,000 | +25% |
| Temperature drop | 20°C | 15°C | −25% |
| Follower increase | 2,400 | 3,000 | +25% |
| Electricity bill | £120 | £150 | +25% |
| Stock price drop | $250 | $200 | −20% |
Percentage increase vs percentage decrease
The same formula works for both increases and decreases. If the new value is higher than the old value the result is positive (increase). If the new value is lower the result is negative (decrease). You do not need a separate formula for each direction.
Note that a 50% increase followed by a 50% decrease does not return you to the starting point. A 50% increase on $100 gives $150. A 50% decrease on $150 gives $75 — not $100. This is because each percentage is calculated on a different base value.
Real-world uses
- Finance — compare investment returns, track portfolio growth, calculate interest rate changes.
- Retail — measure sales growth, compare prices between periods, evaluate discount impact.
- Health & fitness — track weight change, monitor blood pressure, measure performance improvement.
- Business — report revenue growth, measure cost changes, compare monthly or quarterly results.
- Education — compare test scores, measure class averages, track improvement over time.
Also on this site
- Percentage Calculator — find X% of Y, or what percent X is of Y
- Help & Examples — step-by-step guide to all calculators
FAQ
What is the formula for percentage change?
Percentage change = ((New Value − Old Value) ÷ Old Value) × 100. A positive result means an increase; a negative result means a decrease.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the original value, then multiply by 100. For example, an increase from 50 to 75: (75 − 50) ÷ 50 × 100 = 50%.
How do I calculate a percentage decrease?
Use the same formula. Because the new value is smaller than the old value, the result will be negative. For example, a drop from 200 to 150: (150 − 200) ÷ 200 × 100 = −25%.
What is the difference between percentage change and percentage points?
Percentage change is a relative measure. Percentage points are an absolute difference between two percentages. If a tax rate rises from 20% to 25%, that is a 5 percentage point increase, but a 25% relative increase.
Can percentage change be more than 100%?
Yes. If a value doubles it has increased by 100%. If it triples it has increased by 200%. There is no upper limit on percentage increase. Percentage decrease, however, cannot exceed −100% (which would mean the value has reached zero).
How do I reverse a percentage change?
To find the original value before a known percentage change, divide the new value by (1 + change/100). For example, if a price of $120 reflects a 20% increase, the original price was 120 ÷ 1.20 = $100.