Percentage Increase & Decrease Calculator
Use this calculator when a quantity moved from a known starting value to a new value. The original amount is the base, so the result has a sign: positive for an increase, negative for a decrease. Salary hikes, price cuts, and growth rates all use this formula.
How this is calculated
Subtract the original value from the new value, divide by the original, then multiply by 100. A zero original value cannot be used as a base.
((new − original) / original) × 100
- Find the difference: 65 − 50 = 15.
- Divide by the original: 15 / 50 = 0.30.
- Multiply by 100: 30% increase. From 150 to 120 the same steps give −20%.
A 10% to 12% rate change is a 20% increase of the original rate, and also a 2 percentage-point gap. Use this tool for the relative change.
Not the same as
Change always has a starting value. Nearby tools drop that starting value or measure a different gap.
- Percentage difference Difference is symmetric: swapping the two numbers does not change the answer. Change is not symmetric, because the original value is the base. Open percentage difference
- Percentage points Percentage points subtract two percents. Relative change divides by the old percent. From 10% to 12% is 2 points and a 20% increase. Read about percentage points
Related tools
Percentage-change questions
30%. The difference is 15, and 15 / 50 × 100 = 30.
A 20% decrease. The original value is 150, so (120 − 150) / 150 × 100 = −20%. Using 120 as the base would answer a different question.
Change divides by the original value and can be negative. Difference divides by the average and is always non-negative.
Use reverse percentage. Dividing the new value by 1 plus the rate undoes an increase.
No. It is 2 percentage points, which is a 20% increase of the original rate.
Yes. The practice game uses this same original-to-new formula.