About the Percentage Calculator
Percentages come up constantly — discounts, tips, grades, changes over time — but the exact calculation depends on what you're trying to find. This calculator offers several modes in one clean interface, so you can compute a percentage of a number, figure out what percent one value is of another, or measure percentage increases, decreases, and differences.
How it’s calculated
Percent of a number: result = Y × (X ÷ 100). X is what percent of Y: result = (X ÷ Y) × 100. Percentage change: result = ((new − old) ÷ |old|) × 100. Percentage difference: result = (|a − b| ÷ ((a + b) ÷ 2)) × 100.
Example calculation
25% of 80 is 20. The number 30 is 75% of 40. Going from 50 to 65 is a 30% increase, while going from 65 to 50 is about a 23% decrease. The percentage difference between 40 and 60 is 40%.
Frequently asked questions
What's the difference between percentage change and percentage difference?
Percentage change measures the increase or decrease from an original value to a new value, so direction matters. Percentage difference compares two values relative to their average and is always positive — useful when neither value is a clear starting point.
How do I calculate a discount?
Use 'percent of a number' to find the discount amount — for example, 30% of $80 is $24 off — or use percentage decrease to find the final price after the discount is applied.
Why does the calculator have multiple modes?
Different percentage questions require different formulas. Rather than guessing which one you need, you pick the mode that matches your question and the inputs adjust accordingly.
This calculator provides estimates for educational purposes and should not be considered financial, tax, or legal advice. Your actual figures may vary with lender terms, fees, and market conditions.