Percentage Change Calculator
Enter an old value and a new value to find the percentage change (percent increase or decrease), the amount of change, and the new value as a percent of the old value.
How to calculate percentage change
With an old value and a new value, the calculator finds three numbers.
- Amount of change = new value − old value
- Percentage change (%) = amount of change ÷ old value × 100
- New value as a percent of the old value (%) = new value ÷ old value × 100
For example, if sales rise from 1,200,000 to 1,380,000, the amount of change is 180,000 and the percentage change is 180,000 ÷ 1,200,000 × 100 = 15.00%. The new value is 115.00% of the old value.
A positive result is a percent increase and a negative result is a percent decrease. Subtracting 100 from "new as a percent of old" gives the percentage change.
| What happened | New as a percent of old | Percentage change |
|---|---|---|
| The value rose by 10% | 110% | +10% |
| The value did not change | 100% | 0% |
| The value fell by 25% | 75% | −25% |
Which tool should I use?
- Percentage Change Calculator (this page): you know two values and want to know how much one changed from the other, in percent.
- Percentage Calculator: you know a number and a percentage and want the result, for example "what is 15% of 80" or "increase 200 by 8.5%". The inputs and the answer are the other way around.
When the old value is 0 or negative
This calculator does not show a percentage change when the old value is 0 or negative, and shows only the amount of change.
- Old value 0: you cannot divide by 0, so a percentage change is not defined.
- Old value negative: this is a rule of this calculator, not a universal mathematical rule. Some references divide by the absolute value of the old value instead, but the result is easy to misread (for example, going from −50 to −25 is a smaller loss, yet the result can look like a rise or a fall depending on the formula). To avoid a misleading number, the percentage is left blank.
- New value negative with a positive old value: this works. From 100 to −50, the change is −150 and the percentage change is −150.00%.
Percentage change over other periods
The same calculation works for month over month, quarter over quarter, year over year and day over day changes: enter the earlier value as the old value and the later value as the new value. If you enter values that are three years apart, the result is the total change over those three years, not an average yearly rate.
Examples
| Old value | New value | Change | Percentage change |
|---|---|---|---|
| 1,200,000 | 1,380,000 | +180,000 | +15.00% |
| 80 | 60 | −20 | −25.00% |
| 50 | 50 | 0 | 0.00% |
| 100 | −50 | −150 | −150.00% |
| 3 | 4 | +1 | +33.33% |
Notes
- Percentages are rounded to 2 decimal places. The amount of change is exact.
- If the result rounds to 0.00% but the amounts differ, the direction is still shown as an increase or a decrease.
- A percentage change and a change in percentage points are different things. Going from 4% to 5% is a 1 percentage point change, which is a 25% percentage change.
- Increasing by a percentage and then decreasing by the same percentage does not return to the starting value: 100 up 50% is 150, and 150 down 50% is 75.
- The calculation does not know why the values differ. Changes in conditions (for example, months with different numbers of days) can make a comparison less meaningful.
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. From 80 to 100, that is (100 − 80) ÷ 80 × 100 = 25%.
How do I calculate percent decrease?
Use the same formula. If the new value is smaller, the result is negative, and the size of the number is the percent decrease. From 80 to 60, the result is −25%, a 25% decrease.
What is the difference between percentage change and "new as a percent of old"?
"New as a percent of old" treats the old value as 100%. A value that is 115% of the old one has increased by 15%. Percentage change is that number minus 100.
Why is there no percentage when the old value is 0?
A percentage change divides by the old value, and dividing by 0 is not possible. The amount of change is still shown.