Percentage Calculator
Calculate what a percentage of any number is. Enter a value and percentage to find the result using the formula result = (value × percentage) / 100.
Percentage Change Calculator
Calculate the percentage change between two values. Find how much a number increased or decreased as a percentage using the formula ((new-old)/old)×100.
Percentage Change⧉
+25%
Value increased
Absolute Difference⧉
20.0000
100 − 80
Multiplier⧉
1.25×
New is 1.25× the old value
Reverse Change Needed⧉
-20%
Change needed to go back to old value
Ratio⧉
1.25 : 1
New : Old ratio
Direction⧉
↑ Increase
From 80 to 100
Increase25%
Planning notes, formulas, and examples
About the Percentage Change Calculator
The Percentage Change Calculator determines how much a value has increased or decreased relative to its original amount. This is one of the most common calculations in business, finance, and data analysis, used to measure growth rates, price changes, performance shifts, and more.
Enter the old value and the new value, and the calculator shows the percentage change. A positive result means an increase, while a negative result indicates a decrease. The formula divides the difference by the original value and multiplies by 100.
Percentage change is crucial for comparing data over time. Whether you're tracking stock price movements, year-over-year revenue growth, weight loss progress, or inflation rates, this metric provides a standardized way to express how much something has changed relative to its starting point.
When This Page Helps
Raw differences between numbers can be misleading without context. A $10 increase matters a lot more on a $50 item than on a $10,000 item. Percentage change normalizes differences so you can compare changes across different scales and contexts.
How to Use the Inputs
- Enter the original (old) value.
- Enter the new value.
- Read the percentage change displayed.
- A positive result indicates an increase; negative indicates a decrease.
- Use the absolute difference shown for additional context.
Formula used
Percentage Change = ((New Value − Old Value) / Old Value) × 100
Where:
- Old Value = the starting or reference number
- New Value = the ending or current number
- Result > 0 means increase; Result < 0 means decreaseExample Calculation
Result: 25%
The difference is 100 − 80 = 20. Divide by the old value: 20 / 80 = 0.25. Multiply by 100 to get 25%. So the value increased by 25% from 80 to 100.
Tips & Best Practices
- Always use the original (starting) value as the denominator, not the new value.
- A 50% increase followed by a 50% decrease does NOT return you to the original value — you'll be at 75%.
- For financial reports, specify the time period over which the change occurred.
- If the old value is zero, percentage change is mathematically undefined — use absolute change instead.
- To annualize a percentage change over N years, use: ((1 + change/100)^(1/N) − 1) × 100.
- Percentage point change is different from percentage change — going from 10% to 15% is a 5 percentage point increase but a 50% change.
Percentage Change vs. Absolute Change
Absolute change is simply the raw difference between two numbers. Percentage change contextualizes that difference relative to the starting value. A $1,000 increase in salary means very different things for someone earning $30,000 versus $300,000. Percentage change captures this distinction.
Common Applications
Percentage change is used in stock market analysis (daily/yearly returns), economics (GDP growth, inflation), retail (same-store sales growth), health (weight change), and education (test score improvements). It is the universal metric for tracking progress over time.
Compounding and Percentage Change
When changes compound over multiple periods, you cannot simply add percentages. A 10% gain followed by a 10% gain is not 20% total — it is 21% (1.10 × 1.10 = 1.21). Understanding compounding is essential for accurate financial analysis and long-term projections.
Sources & Methodology
Last updated:
Frequently Asked Questions
Percentage change equals the difference between new and old values, divided by the old value, times 100. The formula is ((New − Old) / Old) × 100. This gives you the relative change as a percentage.
When the old value is zero, percentage change is undefined because you cannot divide by zero. In such cases, report the absolute change instead or use a different baseline for comparison.
No. Percentage change uses one specific value as the reference (the old value). Percentage difference uses the average of both values as the reference, making it symmetric regardless of which value you call "old" or "new."
A negative result means the value decreased. For example, −25% means the new value is 25% less than the old value. This is common when tracking price drops, weight loss, or declining metrics.
Because the base changes. If 100 increases by 50%, it becomes 150. Then 50% of 150 is 75, so decreasing by 50% gives 75, not 100. The bases for the two percentage calculations are different.
Businesses use it to measure revenue growth, cost changes, customer acquisition rates, conversion rate improvements, and KPI tracking. It's the standard metric for quarterly and annual performance reports.
More in this topic
Percentage Increase Calculator
Calculate the result after increasing a number by a given percentage. Uses the formula result = value × (1 + pct/100) for instant percentage increase results.
Percentage Decrease Calculator
Calculate the result after decreasing a number by a given percentage. Uses the formula result = value × (1 − pct/100) for discount and reduction calculations.