How to Calculate Percentage Increase (and Decrease)
Quick answer
Percentage increase = (new value − old value) ÷ old value × 100. If a price goes from $80 to $100, the increase is ($100 − $80) ÷ $80 × 100 = 25%. If the answer is negative, it is a percentage decrease.
Free tool
Percentage Calculator. Work out a percentage of a number, what percent one number is of another, and percentage increase or decrease.
You can check any of the examples below with the percentage change box in our percentage calculator.
Step by step
- Subtract the old value from the new value. This is the change.
- Divide the change by the old value.
- Multiply by 100 to turn it into a percent.
Worked examples
| From | To | Change | Percent change |
|---|---|---|---|
| $80 | $100 | +$20 | +25% |
| $1,200 rent | $1,320 rent | +$120 | +10% |
| 50 visitors | 125 visitors | +75 | +150% |
| $250 | $200 | −$50 | −20% |
| 40 hours | 30 hours | −10 | −25% |
Percentage decrease
Use the same formula. When the new value is smaller, the answer comes out negative, and that is your decrease. Some people prefer to write it as (old − new) ÷ old × 100 so the decrease shows as a positive number. A drop from $250 to $200 is ($250 − $200) ÷ $250 × 100 = 20% lower.
In Excel or Google Sheets
Put the old value in A2 and the new value in B2, then type =(B2-A2)/A2 in C2 and format C2 as a percent. Both programs show 0.25 as 25% once the cell is set to percent format.
Mistakes to avoid
- Dividing by the new value. Always divide by the starting value. Going from 80 to 100 is a 25% increase, but going from 100 to 80 is a 20% decrease.
- Mixing up percent and percentage points. If an interest rate moves from 3% to 4%, it rose by 1 percentage point, which is a 33.3% increase.
- Expecting an increase and decrease to cancel out. $100 up 50% is $150. $150 down 50% is $75, not $100.
- Starting from zero. You cannot work out a percentage increase from 0, because you would be dividing by zero.
Work backwards to the original value
If you know the new value and the percent increase, divide by (1 + percent ÷ 100). After a 20% raise, a $60,000 salary was $60,000 ÷ 1.20 = $50,000 before the raise.
Frequently asked questions
What is the formula for percentage increase?
(New value − old value) ÷ old value × 100.
Can a percentage increase be more than 100%?
Yes. Anything that more than doubles has gone up by more than 100%. Going from 50 to 125 is a 150% increase.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value to a starting value. Percentage difference compares two values with no starting point, and divides the gap by their average.
How do I add a percentage increase to a number?
Multiply by (1 + percent ÷ 100). A 15% increase on 200 is 200 × 1.15 = 230.
