MATHEMATICAL GUIDE
How to Calculate a Percentage
Learn how to calculate percentages with precision, convert decimals, and apply the three fundamental percentage formulas to everyday problems.
Decimal Conversions
Convert between percentages, fractions, and decimals effortlessly.
Primary Equations
Understand the three core permutations of Part = Percent × Whole.
Everyday Math
Practical examples covering discounts, tips, tax, and proportions.
1. The Fundamental Percentage Equation
All elementary percentage relationships stem from one core equation:
Part = (Percentage ÷ 100) × Whole
Depending on which quantity is known, you can solve for any of the three components:
- • Find Part: Part = (P ÷ 100) × Whole
- • Find Percentage: P = (Part ÷ Whole) × 100
- • Find Whole: Whole = Part ÷ (P ÷ 100)
2. Interactive Calculator
Use our dedicated tool to calculate any of these relationships instantly:
Frequently Asked Questions
What does the word percentage actually mean?
Percentage originates from the Latin 'per centum', meaning 'by the hundred'. It represents a dimensionless ratio or fraction with 100 as the implied denominator.
How do I convert a percentage into a decimal?
Divide the percentage number by 100 or move the decimal point two places to the left. For example, 75% becomes 0.75, 5% becomes 0.05, and 125% becomes 1.25.
How do I calculate what percentage one number is of another?
Divide the part by the total whole, then multiply by 100: (Part ÷ Whole) × 100. For example, 25 out of 200 is (25 ÷ 200) × 100 = 0.125 × 100 = 12.5%.