Percentage Calculator

A percentage is a way of expressing a number as a fraction of 100. It's calculated by dividing the part by the whole and multiplying by 100. For example, if you scored 85 out of 100 on a test, your percentage is (85 ÷ 100) × 100 = 85%.

Percentage refers to a proportion out of 100, while percentage points refer to the arithmetic difference between two percentages. For example, if a rate increases from 10% to 15%, that's a 5 percentage point increase, but a 50% relative increase.

Percentage increase is calculated using the formula: ((New Value - Old Value) ÷ Old Value) × 100. This shows how much something has grown relative to its original value.

• Find the difference between new and old values
• Divide the difference by the original value
• Multiply by 100 to get the percentage
• Example: From $100 to $120 = ((120-100) ÷ 100) × 100 = 20% increase

Percentage decrease uses the same formula as increase: ((Old Value - New Value) ÷ Old Value) × 100. The result will be positive, representing the percentage by which the value decreased.

Compound percentages apply percentage changes to already changed values. For example, a 10% increase followed by a 10% increase doesn't equal 20% total increase, but rather 21% because the second increase applies to the already increased amount.

Our calculator uses precise mathematical formulas and JavaScript's built-in number handling to provide accurate results. All calculations are rounded to appropriate decimal places for practical use while maintaining mathematical precision.

Percentage calculations are essential in business for various purposes:

• Calculating markup and profit margins on products
• Determining discount rates and sale prices
• Analyzing growth rates and performance metrics
• Computing commission rates and bonuses
• Calculating tax rates and financial ratios
• Measuring market share and competitive analysis