Percentage Calculator
Quickly calculate percentages, find what percentage one number is of another, and determine percentage increases or decreases with our free online tool.
What is 10% of 100?
Comprehensive Guide to Percentage Calculations
A percentage (from Latin per centum "by a hundred") is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%". Percentages are ubiquitous in modern life, used everywhere from financial reports and tax calculations to statistics, science, and daily shopping.
Understanding how to calculate percentages is a fundamental skill. Whether you are figuring out a tip at a restaurant, calculating savings during a sale, or analyzing data growth, the math remains consistent.
The Three Core Percentage Formulas
1. Find Value from Percentage
Use this when you know the total and the percentage you want to find.
2. Find Percentage of a Total
Use this to find what percentage one number is of another.
3. Percentage Change (Increase/Decrease)
Use this to find the growth or decline between two values.
Common Real-World Examples
- Financial InterestCalculating 5% annual interest on a $10,000 savings account balance.
- Sales TaxAdding an 8.25% state tax to a retail purchase price of $150.
- Business GrowthMeasuring a 20% increase in website traffic from one month to the next.
- Academic GradesDetermining that getting 45/50 on a test is equivalent to a 90% score.