Percentage Change Calculator
Calculate the percentage change between two numbers. Find increase or decrease as a percentage instantly.
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The percentage change calculator finds the exact percentage increase or decrease between two numbers. Enter the original value and the new value to instantly see whether the change is positive (increase) or negative (decrease), and by exactly how much. Percentage change is one of the most frequently needed calculations in everyday life: tracking price increases on shopping receipts, measuring salary raise percentages, calculating investment returns, monitoring business metric changes month-over-month, and evaluating grade improvements between test scores. This tool handles all of those cases — positive results indicate an increase (displayed with a green badge), negative results indicate a decrease (red badge). The formula uses the absolute value of the original to correctly handle cases where the original value is negative, such as calculating percentage change in profit when a business moves from a loss to a profit.
How to Use the Percentage Change Calculator
The Percentage Change Calculator is designed to give you an accurate answer in seconds. Follow these steps:
- 1Enter your original value in the Original Value field. The default is 100. Adjust this to match your specific situation.
- 2Enter your new value in the New Value field. The default is 120. Adjust this to match your specific situation.
- 3Click Calculate to see your results instantly. The output updates as soon as you submit.
No account or sign-up required. All calculations run locally in your browser — nothing is stored or transmitted to any server.
Example Calculation
Here is what the Percentage Change Calculator produces with its default values. Change any input above to recalculate instantly for your own figures.
Inputs
- Original Value100
- New Value120
Results
- Percentage Change20.00%
How It Works
Percentage Change (%) = ((New Value − Original) ÷ |Original|) × 100
The formula divides the absolute change (new minus original) by the absolute original value, then multiplies by 100 to express the result as a percentage: Percentage Change (%) = ((New Value − Original) ÷ |Original|) × 100 Example: price increases from £80 to £100. Change = ((100 − 80) ÷ 80) × 100 = (20 ÷ 80) × 100 = 25% increase Example: exam score drops from 85 to 68. Change = ((68 − 85) ÷ 85) × 100 = (−17 ÷ 85) × 100 = −20% (a 20% decrease) Note the difference between percentage change and percentage points. If an interest rate rises from 2% to 3%, it has increased by 1 percentage point but by 50% in relative terms. This calculator measures the relative percentage change.
Frequently Asked Questions
How do I calculate percentage change?
Subtract the original value from the new value, divide by the absolute value of the original, then multiply by 100. Formula: ((New − Original) ÷ |Original|) × 100. A positive result is an increase; negative is a decrease. Example: from 50 to 75 → ((75 − 50) ÷ 50) × 100 = 50% increase. From 100 to 85 → ((85 − 100) ÷ 100) × 100 = −15% (a 15% decrease).
What is the difference between percentage change and percentage points?
Percentage change is the relative change expressed as a fraction of the original. Percentage points measure the arithmetic difference between two percentage values. If the unemployment rate falls from 5% to 4%, it dropped by 1 percentage point but by 20% in relative terms. This calculator measures relative percentage change. Percentage points are used when comparing two rates or percentages directly.
How do I calculate a percentage increase?
Use the formula: ((New − Original) ÷ Original) × 100. If a price rises from $40 to $52: ((52 − 40) ÷ 40) × 100 = (12 ÷ 40) × 100 = 30% increase. To quickly check: if the result is positive, it is an increase. This calculator shows a green indicator for increases and a red indicator for decreases.
Can I calculate percentage change if the original value is negative?
Yes — this calculator uses the absolute value of the original (|original|) in the denominator to handle negative starting values correctly. If a business had a loss of −$50,000 and now has a profit of $30,000: ((30,000 − (−50,000)) ÷ 50,000) × 100 = (80,000 ÷ 50,000) × 100 = 160% change. If the original is zero, percentage change is mathematically undefined — dividing by zero has no answer.
Is the percentage change calculator free?
Yes — completely free with no sign-up required. Enter your original and new values for an instant result. All calculations run in your browser and no data is stored.