Percentage Increase Calculator
Enter your original value and your new value. The calculator will instantly show the amount of change and the percentage increase (or decrease).
What is a percentage increase?
A percentage increase tells you how much something has gone up compared to where it started. Instead of just saying “it increased by 20,” percentage increase gives context by expressing the change relative to the original value.
For example, a $20 increase means very different things if the original value was $40 versus $2,000. Percentage makes that difference clear.
The percentage increase formula
Use this standard formula:
Percentage Increase = ((New Value - Original Value) / Original Value) × 100
There are three parts:
- New Value - Original Value gives the amount of change.
- Divide by Original Value to compare the change to the starting point.
- Multiply by 100 to convert to a percent.
Step-by-step example
Example: Price rises from 50 to 65
- Original Value = 50
- New Value = 65
- Change = 65 - 50 = 15
- Relative change = 15 / 50 = 0.30
- Percentage Increase = 0.30 × 100 = 30%
So the price increased by 30%.
Another practical example (salary)
Suppose your salary goes from $48,000 to $52,800.
- Change = 52,800 - 48,000 = 4,800
- Relative change = 4,800 / 48,000 = 0.10
- Percentage Increase = 0.10 × 100 = 10%
Your raise is a 10% increase.
Percentage increase vs. percentage points
This is a common confusion:
- Percentage points = direct subtraction between percentages.
- Percentage increase = relative change between percentages.
If a rate moves from 20% to 25%, that is:
- +5 percentage points
- 25% percentage increase because (25 - 20) / 20 = 0.25
Common mistakes to avoid
1) Dividing by the new value instead of the original value
The denominator should almost always be the original value when calculating increase from a starting point.
2) Forgetting to multiply by 100
After dividing, you usually get a decimal. Multiply by 100 to convert to percent.
3) Ignoring decreases
If the result is negative, it is a percentage decrease, not an increase.
4) Starting from zero
If the original value is zero, the standard percentage increase formula is undefined because you cannot divide by zero. In those cases, describe the absolute increase instead.
Quick mental math tips
- 10% of a number is easy: move decimal one place left.
- 5% is half of 10%.
- 1% is 10% divided by 10.
- To estimate a 12% increase: add 10% + 2%.
These shortcuts are useful for shopping discounts, budget changes, and interpreting financial news quickly.
Where percentage increase is useful
- Tracking revenue growth in business
- Measuring investment performance
- Comparing rent or home price changes
- Evaluating inflation impact on expenses
- Reviewing school test score improvement
Practice problems
Try these
- From 120 to 150
- From 75 to 90
- From 320 to 400
Answers
- (150 - 120) / 120 × 100 = 25%
- (90 - 75) / 75 × 100 = 20%
- (400 - 320) / 320 × 100 = 25%
Final takeaway
To calculate percentage increase, always compare the change to the original amount:
((New - Original) / Original) × 100
Use the calculator above for quick answers, and use the manual method when you want to understand exactly what the numbers mean.