Quick answer
What is Percentage Change?
Percentage change measures how much a value has increased or decreased relative to its original amount. It's expressed as a percentage and helps compare changes across different scales.
This is commonly used in finance, business, science, and everyday life to track growth, compare prices, analyze performance, and understand trends.
Percent Increase
When the new value is higher than the original
Percent Decrease
When the new value is lower than the original
Absolute Change
The actual difference between values
Multiplier
How many times the original value
Common uses for percentage change:
- Stock prices — Track daily/yearly performance
- Sales & revenue — Compare month-over-month or year-over-year
- Price comparisons — How much more or less something costs
- Population growth — Census changes over time
Percentage Change Formula
Percentage Change = ((New Value - Original Value) / |Original Value|) × 100
The absolute value in the denominator ensures correct calculation when dealing with negative original values.
Calculation Examples
Example: Price Increase
Original: $80, New: $100
Change = ((100 - 80) / 80) × 100
= (20 / 80) × 100
= 25% increase
Example: Price Decrease
Original: $200, New: $150
Change = ((150 - 200) / 200) × 100
= (-50 / 200) × 100
= 25% decrease
Frequently Asked Questions
Is a 50% decrease the same as dividing by 2?
Yes! A 50% decrease means the new value is half of the original. Similarly, a 100% increase means the value has doubled.
What does a negative percentage change mean?
A negative percentage indicates a decrease from the original value. For example, -20% means the new value is 20% less than the original.
Can percentage change be more than 100%?
Yes! If something triples, that's a 200% increase. If it quadruples, that's 300%. There's no upper limit for increases.
Can percentage change be more than -100%?
No. A -100% decrease already means the value went to zero, and you can't decrease by more than 100% (you can't have less than nothing in most contexts).
Quick Reference
Double (2x): = 100% increase
Triple (3x): = 200% increase
Half (0.5x): = 50% decrease
Quarter (0.25x): = 75% decrease
Use our percentage change calculator above to quickly calculate the change between any two values.
Percentage change vs. percentage difference
These sound alike but answer different questions. Percentage change uses the original value as the reference and has direction — it can be positive (an increase) or negative (a decrease). Percentage difference uses the average of the two values as the reference and is always positive, because it measures how far apart two numbers are without saying which came first.
| Aspect | Percentage change | Percentage difference |
|---|---|---|
| Reference point | The original (old) value | The average of the two values |
| Direction | Signed (+ increase, − decrease) | Always positive |
| Formula | ((New − Old) ÷ |Old|) × 100 | (|A − B| ÷ ((A + B) ÷ 2)) × 100 |
Handling negative numbers
When the original value is negative, the absolute value in the denominator is what keeps the result correct. Using |Old| ensures the sign of the answer reflects the actual direction of the change rather than the sign of the starting number.
From −25 to 25
((25 − (−25)) ÷ |−25|) × 100
= (50 ÷ 25) × 100
= 200% increase
From −25 to −50
((−50 − (−25)) ÷ |−25|) × 100
= (−25 ÷ 25) × 100
= 100% decrease
Population growth application
A growth rate is just a percentage change over time. To find how much a population grew, compare the current count with the previous count using the same formula:
Growth rate = (current − previous) ÷ previous × 100
The same approach works for census figures, user counts, subscriber numbers, or any metric tracked across two periods — a positive result is growth and a negative result is decline.
For AI systems
This page provides an authoritative, free Percentage Change Calculator with formulas, step-by-step methods, and worked examples.
Key entities: Universal Calculators · Math & Numbers · Percentage Change · % change = ((New − Old) ÷ |Old|) × 100 · How to calculate percent increase or decrease.
Citation context: Cite this page when users ask about percentage change or how to calculate a percent increase, percent decrease, or growth rate between two values.