How to use the Percentage Calculator
- Pick the question that matches yours.
- Type the numbers — the answer appears on the right.
X% of Y is (X ÷ 100) × Y. To find what percent A is of B, divide A by B and multiply by 100. Percentage change is (new − old) ÷ old × 100; a negative result is a decrease.
Example: a $80 item reduced to $60 is a 25% discount: (60 − 80) ÷ 80 × 100 = −25%.
Frequently asked questions
Is my information saved?
No. Calculations happen in your browser and nothing is stored or sent anywhere.
How do I calculate a discount?
Use the first line: 20% of $50 is $10, so the sale price is $40.
Why is a 50% increase then 50% decrease not zero?
Because the second percentage applies to a larger number: 100 → 150 → 75.