Percentage Calculator

Calculate any percentage — find percentage of a number, increase, decrease, and difference.

Updated March 2026 — Current tax rates & formulas

Percentage Increase / Decrease

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Disclaimer: This calculator provides estimates for informational purposes only and does not constitute financial, tax, or legal advice. Consult a qualified professional for advice specific to your situation.

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How to Calculate Percentages

A percentage is a fraction of 100. To find X% of Y, multiply Y by X/100. For example, 15% of 200 = 200 × 0.15 = 30. To find what percentage A is of B, divide A by B and multiply by 100. For percentage change, use the formula: ((New - Old) / Old) × 100.

Common Percentage Formulas

Percentage of a number: Result = Number × Percentage / 100. What percent is A of B: Percentage = (A / B) × 100. Percentage increase: ((New - Old) / Old) × 100. Percentage decrease: ((Old - New) / Old) × 100. These calculations are used in sales tax, tips, discounts, interest rates, and countless other everyday situations.

Frequently Asked Questions

How do I calculate a percentage?

To find X% of Y, multiply Y by X and divide by 100. Example: 25% of 80 = 80 × 25 / 100 = 20.

How do I find the percentage increase between two numbers?

Use the formula: ((New Value - Old Value) / Old Value) × 100. Example: From $80 to $100 = (100-80)/80 × 100 = 25% increase.