Find percentage increase, decrease or difference between two values instantly.
Change uses the old value as base; difference uses the average.
Percentages are everywhere: sales figures rising or falling, prices going up, exam scores, weight tracked over time, and countless comparisons in business and daily life. Two closely related but genuinely different questions come up constantly. First, how much did something change from one value to another? Second, how far apart are two values, when neither one is clearly the "starting point"? These are answered by percentage change and percentage difference, and mixing them up is one of the most common numerical mistakes people make.
Our Percentage Change & Difference Calculator handles both. Switch between modes, enter your two values, and get an instant, accurate result with full step-by-step working. It is free, works on any device and needs no sign-up.
Percentage change measures how much a value has increased or decreased relative to its original, starting value. It is directional: going from 50 to 75 is a different percentage than going from 75 to 50, even though the two numbers are the same.
Percentage Change = ((New Value − Old Value) ÷ Old Value) × 100
A positive result means an increase, and a negative result means a decrease.
Example: a product's price rises from $50 to $75.
Change = ((75 − 50) ÷ 50) × 100 = (25 ÷ 50) × 100 = 50% increase
Example: a stock falls from $80 to $60.
Change = ((60 − 80) ÷ 80) × 100 = (−20 ÷ 80) × 100 = −25%, a 25% decrease
A company's quarterly revenue rises from $200,000 to $260,000.
Change = ((260,000 − 200,000) ÷ 200,000) × 100 = (60,000 ÷ 200,000) × 100 = 30% increase
This single number, a 30% quarter-over-quarter increase, is far easier to compare across companies of different sizes than the raw dollar figure alone, which is exactly why percentage change is the standard way analysts report growth.
Percentage difference measures how far apart two values are, without treating either one as the "before" value. It is symmetric: comparing 50 to 75 gives the same percentage difference as comparing 75 to 50. This makes it useful when you are comparing two independent measurements, such as two competing products, rather than tracking one thing changing over time.
Percentage Difference = (|Value 1 − Value 2| ÷ ((Value 1 + Value 2) ÷ 2)) × 100
Example: two stores price the same item at $50 and $75.
Average = (50 + 75) ÷ 2 = 62.5
Difference = (|50 − 75| ÷ 62.5) × 100 = (25 ÷ 62.5) × 100 = 40%
Notice this is a different number from the 50% we got for percentage change between the same two values, because the base used in the calculation is different.
Two surveys, run independently, find that 40% and 46% of respondents prefer a certain product. Since neither survey is the "original" and neither came before the other, percentage difference is the appropriate measure here.
Average = (40 + 46) ÷ 2 = 43
Difference = (|40 − 46| ÷ 43) × 100 = (6 ÷ 43) × 100 ≈ 13.95%
This tells you how far apart the two survey results are relative to their shared average, without implying one is a "before" and the other an "after."
| Percentage Change | Percentage Difference | |
|---|---|---|
| Use Case | Tracking one value over time | Comparing two independent values |
| Base Used | The old/original value | The average of both values |
| Direction | Can be positive (increase) or negative (decrease) | Always a positive, absolute figure |
| Symmetric? | No, order matters | Yes, order does not matter |
| Example Use | Sales growth, price changes, stock returns | Comparing two products, two survey results |
| Scenario | Old | New | % Change |
|---|---|---|---|
| Salary raise | $50,000 | $55,000 | +10% |
| Weight loss | 80 kg | 72 kg | −10% |
| Website traffic | 2,000 visits | 3,500 visits | +75% |
| Stock price | $120 | $90 | −25% |
These two are frequently confused. If an interest rate rises from 5% to 8%, that is a rise of 3 percentage points, but it is a 60% increase in the rate itself (3 ÷ 5 × 100). News reports sometimes blur this distinction, so always check whether a figure is describing a percentage-point shift or a percentage change.
Percentage change can be calculated with negative old or new values, such as temperature changes or profit/loss figures, but the results can be less intuitive to interpret. Always double-check that a negative-to-positive or positive-to-negative transition makes sense in context before relying on the percentage figure alone; in these cases, looking at the raw difference alongside the percentage is often clearer.
Percentage change always divides by the old value, not the new one. Dividing by the new value instead gives a different, incorrect answer.
A decrease should show as a negative percentage change. Dropping the sign can make a decline look like an increase in a report.
As shown above, they use different formulas and produce different results for the same pair of numbers. Choose the one that matches your actual question.
If the old value is 0, percentage change is undefined, since you cannot divide by zero. The calculator will flag this as an error.
Choosing the right formula, percentage change for tracking movement over time, or percentage difference for comparing two independent values, keeps your numbers accurate and your conclusions trustworthy. Use the calculator above to get instant results in either mode, complete with step-by-step working, so you always know exactly how the answer was reached.