Free Percentage Calculator
Three classic percentage problems in one tool: what is X% of Y, X is what percent of Y, and the percentage change from X to Y. Pick the type, enter two numbers, done.
How to Use the Percentage Calculator
- Choose the type of percentage problem.
- Enter X and Y.
- Click Calculate for the answer.
Features
Implements each formula directly with guards against division by zero, and labels results with the formula used so you can learn the math, not just the answer.
Benefits & Use Cases
Students check homework, shoppers compute discounts and tips, analysts express shares and changes — the three modes cover most daily percent needs.
Tips
For “X is what % of Y”, double-check which number is the part and which is the whole — swapping them is the classic mistake.
Frequently Asked Questions
How do I find X% of Y?
Multiply: (X ÷ 100) × Y. E.g. 20% of 150 = 30.
How do I find what percent X is of Y?
Divide: (X ÷ Y) × 100. E.g. 30 is 20% of 150.
What is percentage change?
(New − old) ÷ old × 100 — positive for growth, negative for decline.
Why do I get an error with zero?
Percentages need a non-zero base for division; the tool explains which input to fix.
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