Percentage Calculator

Percentage Calculator – Quick Cheat Sheet

• What is A% of B? → (A ÷ 100) × B
• A is what percent of B? → (A ÷ B) × 100%
• Percent change from A to B → ((B − A) ÷ A) × 100%
• Increase B by A% → B × (1 + A ÷ 100)
• Decrease B by A% → B × (1 − A ÷ 100)
• Tip: Use decimals for precise inputs (e.g., 12.5 for 12½%).
• Validation: For “A is what % of B?” B ≠ 0. For “Percent change,” A ≠ 0.