Percentage Change Calculator
Find out by what percentage something went up or down, like a price, a salary, or a bill. You can also apply a percentage increase or decrease to any number.
Increase
+25.00%
Check the highlighted fields to see your result.
- Difference
- 20
- Times the initial value
- 1.25×
Results are estimates for information only and do not constitute financial, medical, or legal advice.
How percentage change works
The percentage change compares the difference between two values with the starting value. A positive result is an increase and a negative one is a decrease. To apply a change, multiply the value by (1 + percentage ÷ 100).
The formulas
Change = (final − initial) ÷ initial × 100
New value = value × (1 + percentage ÷ 100)
Worked example
Your rent goes from 1,250 to 1,400.
- Difference: 1,400 − 1,250 = 150.
- Change: 150 ÷ 1,250 × 100 = 12% increase.
- The other way around: 1,250 × (1 + 0.12) = 1,250 × 1.12 = 1,400.
Frequently asked questions
Why does a 20% increase followed by a 20% decrease not get me back to the start?
Because each percentage is taken from a different starting value. 100 plus 20% is 120, but 20% of 120 is 24, so going down 20% leaves 96, not 100.
Is going from 80 to 100 the same percentage as going from 100 to 80?
No. From 80 to 100 is a 25% increase (20 ÷ 80), but from 100 to 80 is a 20% decrease (20 ÷ 100). The change is always divided by the starting value.
What if the initial value is negative?
The calculator divides by the absolute value of the initial number, so a move from −50 to −25 shows as a 50% increase. With negative values, read the result with care.