📊 Percentage Calculator
All percentage calculations in one place. Ratios, percent change, discounts, and more.
Find what B% of a number is
Percentage Formulas
📐 B% of A
A × B ÷ 100 — The most basic percentage calculation. Used for tips, taxes, discounts, and more.
📊 What % is A of B?
A ÷ B × 100 — Find scores, completion rates, and proportions.
📈 Percent Change
(New − Old) ÷ |Old| × 100 — Track revenue growth, price changes, stock performance.
💰 Apply Percentage
Increase: A × (1 + B/100) | Decrease: A × (1 − B/100) — Price markups, salary raises, discounts.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30. Use the "B% of A" mode in the calculator above.
How do I calculate percent change?
Percent change = (New Value − Old Value) ÷ |Old Value| × 100. For example, if a price went from $100 to $120, the change is (120 − 100) ÷ 100 × 100 = 20% increase.
How do I calculate a discount?
Use the "Apply %" mode with Decrease. For example, a $50 item with 30% off: $50 × (1 − 30%) = $35. You can also use "B% of A" to find just the discount amount.