Percentage Change Calculator
Calculate the percentage change between two values, whether it's an increase or decrease, instantly.
Percentage Change
Increase or decrease between two values
Result = ((New - Old) / |Old|) * 100 No calculations yet.
How to Calculate
Result = ((New − Old) ÷ |Old|) × 100
The formula subtracts the original value (Old) from the current value (New) to determine the absolute change. This difference is then divided by the absolute value of the original value (|Old|). Multiplying the result by 100 converts the ratio into a percentage. If the result is positive, it signifies a percentage increase; if negative, it signifies a percentage decrease.
* Example: From 50 to 75 → +50% change
Step-by-Step Manual Calculation Guide
Step 1: Calculate the absolute change by subtracting the old value from the new value: (New − Old).
Step 2: Divide the change by the original (old) value.
Step 3: Multiply the quotient by 100 to convert to a percentage. Maintain the positive or negative sign to indicate direction.
Real-World Industry Applications
Stock Investment Tracking
Evaluating quarterly portfolio growth when a stock price moves from $50 per share to $65 per share (+30% change).
Inflation Rate Measurement
Assessing year-over-year consumer price index shifts from 250 to 265 (+6% inflation rate).
Website Traffic Metrics
Analyzing monthly active user changes when web traffic shifts from 10,000 visitors down to 8,500 visitors (-15% change).
Percentage Change Worked Examples
How it Works
Percentage change measures the relative variation between an old value and a new value over time. Unlike absolute change (which simply tells you the difference in units or dollars), percentage change contextualizes growth or decline relative to the starting point. This makes it an essential metric for stock market performance, inflation metrics, sales growth reporting, and scientific comparisons.
Related Calculators
Frequently Asked Questions
What's the difference between percentage change and percentage difference?
Percentage change has a chronological direction because it compares a starting 'old' value to a later 'new' value. Percentage difference is directionless and compares two values without specifying one as the baseline, dividing by their average instead.
Can percentage change be negative?
Yes, a negative percentage change indicates that the new value is smaller than the old value, representing a decrease or loss. For instance, moving from $100 to $80 represents a -20% change.
How do I calculate percentage change by hand?
First, subtract the old value from the new value. Next, divide that result by the old value. Finally, multiply by 100. For example, moving from 40 to 50: (50 - 40) = 10; 10 / 40 = 0.25; 0.25 × 100 = +25%.
How do I calculate percentage change if the original value is negative?
When the original starting value is negative, you must use the absolute value (magnitude) of the original number in the denominator. Otherwise, the sign of the percentage change will be inverted and mathematically misleading.
What does a 100% increase mean?
A 100% increase means the value has exactly doubled. For example, if an item's price goes from $50 to $100, the increase is $50, which is 100% of the original $50 base price.