Percentage Calculator

Calculate percentages, find percentage changes, determine what percentage one number is of another, and more.

Understanding Percentages

A percentage is a number expressed as a fraction of 100. The symbol "%" represents percentage. For example, 50% means 50 out of 100, or 0.5 as a decimal.

Mathematically, to find X% of Y, we calculate (X × Y) ÷ 100.

Common Calculations

Finding a Percentage

To find X% of Y, multiply Y by X/100.

Example: 20% of 80 = (20 × 80) ÷ 100 = 16

Percentage of a Total

To find what percentage X is of Y, divide X by Y and multiply by 100.

Example: 15 is what % of 60? (15 ÷ 60) × 100 = 25%

Percentage Change

To find the percentage change, subtract old value from new value, divide by old value, and multiply by 100.

Example: Change from 50 to 60: ((60 - 50) ÷ 50) × 100 = 20% increase

Applications

Discounts

Calculate sale prices after percentage discounts.

Tips

Calculate gratuity amounts based on bill totals.

Tax Calculations

Determine tax amounts based on percentage rates.

Interest Rates

Calculate interest earned or paid on loans/investments.

Percentage Formulas

Finding Percentage

X% of Y = (X × Y) ÷ 100

Percentage of Total

X is what % of Y = (X ÷ Y) × 100

Percentage Change

% Change = ((New - Old) ÷ Old) × 100

Add/Subtract Percentage

Y + X% = Y × (1 + X/100)

Y - X% = Y × (1 - X/100)

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Frequently Asked Questions

Find answers to common questions about Online Calculator.

A Percentage Calculator helps you calculate percentages, percentage increases or decreases, and find what percent one number is of another.

Use the formula: (percentage × number) / 100. For example, 20% of 50 is (20 × 50) / 100 = 10.

Use the formula: (part / total) × 100. For example, if 25 out of 200 people like a product, the percentage is (25 / 200) × 100 = 12.5%.

Use the formula:Percentage Change = [(New Value - Old Value) / Old Value] × 100. For example, if a price increases from $50 to $60, the percentage increase is (60 - 50) / 50 × 100 = 20%.

To find the original value before a percentage change, use:Original Value = Final Value / (1 ± Percentage Change/100). For example, if a price after a 20% increase is $120, the original price was 120 / 1.2 = $100.

Multiply by 100 and add a percent sign (%). For example, 0.75 × 100 = 75% and 3/4 × 100 = 75%.

Use the formula: Final Value = Original Value × (1 ± Percentage/100). For example, if a $200 item gets a 15% discount, the final price is 200 × (1 - 0.15) = $170.

Percentage increase is calculated relative to the smaller original value, while percentage decrease is relative to the larger starting value. For example, increasing from 50 to 100 is a 100% increase, but decreasing from 100 to 50 is only a 50% decrease.

Percent change refers to a relative increase or decrease, while percentage points represent the absolute difference between percentages. For example, if an interest rate goes from 5% to 7%, that is a 2 percentage point increase, but a (2/5) × 100 = 40% relative increase.

If a value grows by a fixed percentage over time, use:Final Value = Initial Value × (1 + Percentage/100)^n, where n is the number of periods. For example, $100 growing by 10% annually for 3 years becomes 100 × (1.1)^3 = $133.10.

To calculate a percentage increase, subtract the original value from the new value, divide by the original value, and multiply by 100. For example, if a price increases from $80 to $100, the percentage increase is ((100 - 80) ÷ 80) × 100 = 25%.

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