How do I calculate percentage?

To calculate a percentage, divide the part by the whole and multiply by 100. For example, if you scored 45 out of 60, the percentage is (45 / 60) × 100 = 75%.

How do I calculate what percent X is of Y?

Divide X by Y and multiply by 100. For example, 25 is what percent of 200? (25 / 200) × 100 = 12.5%.

How do I calculate percentage increase?

Percentage increase = ((new value - original value) / original value) × 100. If a price goes from $80 to $100, the increase is ((100-80)/80) × 100 = 25%.

How do I calculate percentage decrease?

Percentage decrease = ((original value - new value) / original value) × 100. If a price drops from $100 to $80, the decrease is ((100-80)/100) × 100 = 20%.

Percentage Calculator

Calculate percentages, percentage change, increase, and decrease — instant and accurate.

What is X% of Y?

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Step-by-step

Free Online Percentage Calculator

Our free percentage calculator helps you solve any percentage problem instantly. Whether you need to find what percent a number is of another, calculate percentage change, or figure out a discount, our tool gives you the answer with step-by-step explanations.

Percentage Formulas

What is X% of Y? — Multiply Y by X/100. Example: 20% of 150 = 150 × 0.20 = 30.
X is what % of Y? — Divide X by Y, multiply by 100. Example: 30 is what % of 150? (30/150) × 100 = 20%.
Percentage change — ((new − old) / old) × 100. Positive = increase, negative = decrease.
Percentage increase — ((new − old) / old) × 100. Example: 80→100 = ((100−80)/80) × 100 = 25%.
Percentage decrease — ((old − new) / old) × 100. Example: 100→80 = ((100−80)/100) × 100 = 20%.

Common Percentage Uses

Discounts & sales — Calculate sale prices, like 30% off a $50 item
Tips — Figure out 15% or 18% tip on a restaurant bill
Taxes — Add sales tax or VAT to a price
Grades — Calculate test scores as percentages
Finance — Interest rates, investment returns, profit margins
Statistics — Compare data, growth rates, market share

How to Calculate Percentage Quickly

To calculate a percentage mentally, a useful trick is to find 10% first (move the decimal point one place left), then multiply. For example, to find 15% of $40: 10% is $4, half of that (5%) is $2, so 15% = $4 + $2 = $6. Our calculator does this instantly for any numbers — no mental math required.

FAQ

What is a percentage? — A percentage is a number expressed as a fraction of 100. The symbol "%" means "per hundred." So 50% = 50/100 = 0.5.

How is percentage different from a fraction? — A percentage is just a fraction with denominator 100. 25% = 25/100 = 1/4.

Can percentages be over 100%? — Yes. 200% means twice the original amount. This is common in growth calculations.

Is this percentage calculator free? — Yes, completely free. No signup, no download, no limits.