Percentage Formula Explained

This reference explains the Percentage formula used by our free Percentage Calculator. Use it to understand variables, units, and common mistakes before you calculate.

The formula

Result = (percentage ÷ 100) × number

Variables and units

• percentage — The percent value (%)
• number — The base number (any unit)

Worked example

Inputs: What is 15% of 240?

1. Convert percent to decimal: 15 ÷ 100 = 0.15
2. Multiply: 0.15 × 240 = 36

Result: 15% of 240 = 36

When to use this formula

Use this formula when you need a quick percentage estimate with values you already know. Our Percentage Calculator applies the same relationship automatically so you can verify handwritten work.

Common mistakes

• Adding percentages directly (10% + 20% ≠ 30% of the same base in sequential discounts)
• Confusing 'percent of' with 'percent increase'
• Forgetting to convert percent to decimal before multiplying

Frequently asked questions