Percentage Change Calculator
Calculate percentage change, difference, error, and more
From A to B
Result
Enter values and click Calculate
What is the Percentage Change Calculator?
Percentage change tells you how much something has grown or shrunk relative to its original value. It's one of the most-used quick calculations in everyday life: price comparisons, stock returns, sales data, test score improvements, population shifts. This calculator takes two numbers, old and new, and gives you the percentage change between them. CalciHub's version also handles percentage decrease and shows whether the change was a gain or a loss.
How Does It Work?
Subtract the old value from the new value, divide that by the old value, then multiply by 100 to express it as a percentage. A positive result is an increase; a negative result is a decrease.
Percentage Change = ((New Value - Old Value) / Old Value) × 100
• New Value = The value after the change
• Old Value = The original starting value
• Result = Positive means increase, negative means decrease
How to Use CalciHub's Percentage Change Calculator
1. Enter the original (old) value.
2. Enter the new value.
3. Click Calculate.
4. The result shows the percentage change, labeled as an increase or decrease.
Tip: Don't confuse percentage change with percentage points. If a rate goes from 10% to 15%, that's a 5 percentage-point increase, but a 50% change relative to the original 10%.
A Quick Example
A product's price dropped from 80 to 60. What's the percentage change?
• Old Value = 80
• New Value = 60
• Change = (60 - 80) / 80 × 100 = -20 / 80 × 100 = -25%
The price fell by 25%. That's a meaningful discount, and having the exact percentage makes it easy to compare against other products or promotional offers without guessing.
Frequently Asked Questions
The formula breaks down – you can't divide by zero. If the original value is zero, percentage change is mathematically undefined. In practice, you'd describe the change in absolute terms instead (e.g., 'went from 0 to 50').
Yes. A 100% increase means the value grew by an amount equal to itself — so it doubled. A 200% increase means it tripled (original + twice the original). This trips people up more often than it should.
Percentage change goes from a specific old value to a new value — direction matters. Percentage difference compares two values symmetrically without labelling one as 'before' — it's more useful when comparing two things that aren't in a time sequence.
If a value increased by 25%, you can find the original by dividing the new value by 1.25. More generally: Original = New Value / (1 + percentage change/100). This is useful when you know the final price and the markup rate.
Yes, always free.
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