Percentage Calculator
Calculate percentages easily. Find what percent one number is of another, calculate percentage increase or decrease, and more.
📖 How to Use
Choose the type of percentage calculation you need, enter your numbers, and get instant results. This calculator handles all common percentage problems including finding percentages, calculating increases/decreases, and determining what percent one number is of another.
What Can You Calculate?
What is X% of Y?
Find a percentage of any number. Example: What is 15% of 200?
X is what % of Y?
Find what percentage one number is of another. Example: 30 is what % of 150?
Percentage Increase
Calculate the percentage increase from one number to another.
Percentage Decrease
Calculate the percentage decrease from one number to another.
Frequently Asked Questions
❓How do I calculate a percentage?
To find X% of Y, multiply Y by X and divide by 100. For example, 20% of 50 = (50 × 20) ÷ 100 = 10.
❓How do I find percentage increase or decrease?
Percentage change = ((New Value - Old Value) ÷ Old Value) × 100. A positive result is an increase, negative is a decrease.
📐 Common Percentage Formulas
Understanding a few core percentage formulas unlocks the ability to solve almost any percentage problem you encounter. Below are the five most common formulas, each with a clear worked example so you can see exactly how they are applied.
Basic Percentage
Formula: (Part ÷ Whole) × 100
Example: You scored 42 out of 50 on a test. What percentage is that? (42 ÷ 50) × 100 = 84%
Percentage of a Number
Formula: (Percentage ÷ 100) × Number
Example: What is 25% of 200? (25 ÷ 100) × 200 = 0.25 × 200 = 50
Percentage Change
Formula: ((New Value - Old Value) ÷ Old Value) × 100
Example: A stock went from $80 to $100. What is the percentage change? ((100 - 80) ÷ 80) × 100 = 25% increase
Percentage Increase
Formula: Original × (1 + Percentage ÷ 100)
Example: Your rent is $1,200 and increases by 5%. New rent = $1,200 × (1 + 5/100) = $1,200 × 1.05 = $1,260
Percentage Decrease
Formula: Original × (1 - Percentage ÷ 100)
Example: A $60 item is 30% off. Sale price = $60 × (1 - 30/100) = $60 × 0.70 = $42
💡 Real-World Percentage Examples
Percentages are everywhere in daily life, from shopping discounts to financial planning. Here are some practical examples that show just how useful percentage calculations can be in everyday situations.
Shopping Discounts
A $120 jacket is 25% off. To find the sale price, calculate: $120 × 0.75 = $90. When stores stack discounts (e.g., 20% off then an extra 10%), the discounts multiply rather than add: $120 × 0.80 × 0.90 = $86.40 (not 30% off).
Finance & Savings
Your savings account earns 4.5% APY on $10,000, meaning you'll earn approximately $450 per year in interest. Understanding percentage returns helps you compare investment options and project future growth. A credit card with 22% APR on a $5,000 balance costs roughly $1,100 per year in interest.
Grades & Scores
You got 42 out of 50 on a test. Your percentage score = (42 ÷ 50) × 100 = 84%. Teachers, professors, and standardized tests all use percentages to communicate performance. Many grading scales consider 90-100% an A, 80-89% a B, and so on.
Cooking & Recipes
A recipe serves 4, but you need to serve 6 people. That's 150% of the original recipe (6 ÷ 4 = 1.5). Multiply every ingredient by 1.5. If the recipe calls for 2 cups of flour, you'll need 2 × 1.5 = 3 cups. Scaling recipes up or down is one of the most common real-world percentage applications.
More Percentage Questions
❓What's the difference between percentage and percentage points?
This is one of the most commonly confused concepts in math and statistics. A "percentage" describes a relative change, while "percentage points" describe an absolute change. For example, if an interest rate goes from 5% to 7%, it increased by 2 percentage points. However, the percentage increase is actually 40% (because 2 ÷ 5 × 100 = 40%). This distinction matters enormously in finance, politics, and data analysis. When news headlines say "unemployment rose 2%," they often mean 2 percentage points, which could represent a much larger relative change.
❓How do I convert a fraction to a percentage?
To convert a fraction to a percentage, divide the numerator (top number) by the denominator (bottom number), then multiply by 100. For example, 3/8 as a percentage: 3 ÷ 8 = 0.375, then 0.375 × 100 = 37.5%. Some common conversions worth memorizing: 1/4 = 25%, 1/3 ≈ 33.3%, 1/2 = 50%, 2/3 ≈ 66.7%, 3/4 = 75%. To go the other direction (percentage to fraction), put the percentage over 100 and simplify: 75% = 75/100 = 3/4.
❓How do I calculate compound interest with percentages?
Compound interest is calculated using the formula: A = P × (1 + r/n)^(n×t), where P is the principal (starting amount), r is the annual interest rate as a decimal, n is the number of times interest compounds per year, and t is the number of years. For example, $10,000 at 5% compounded monthly for 3 years: A = $10,000 × (1 + 0.05/12)^(12×3) = $10,000 × (1.004167)^36 ≈ $11,614.72. The key difference from simple interest is that compound interest earns interest on previously earned interest, which causes your money to grow exponentially over time.
Want to master everyday percentage calculations? Read our guide: Percentage Calculations You Use Every Day.