Percentage Calculator

Calculate percentages, reverse percentages, percent change, percent difference, and increase or decrease by a percent.

The Percentage Calculator handles everyday percent questions: what is X% of Y, what percent is A of B, and percent change between two numbers. Useful for discounts, grades, stats, and quick checks. What this calculator does Percent problems show up everywhere — sales, tips, exam scores, and growth rates. This tool keeps the three most common patterns in one place. Pick the mode that matches your question, enter the numbers, and read the plain-language result. How the math works Part = percent/100 × whole. Percent = (part ÷ whole) × 100. Percent change = (new − old) ÷ old × 100. Watch the order of “old” and “new” on percent change — swapping them flips the sign of the result.