Percentage Calculator: Calculate Percentages Instantly Online

Why Percentage Calculations Matter

Percentages are everywhere in daily life:

Calculating percentages manually is error-prone. Our Percentage Calculator handles all common scenarios instantly.

Percentage Calculation Modes

1. What is X% of Y?

The most common calculation. Given a percentage and a total, find the portion.

Formula:

Result = (Percentage ÷ 100) × Total

Example:

What is 15% of 200?
= (15 ÷ 100) × 200
= 0.15 × 200
= 30

Real-world use: Calculate a tip on a restaurant bill. Bill is $84.50, you want to leave 18%.

18% of 84.50 = 0.18 × 84.50 = $15.21 tip
Total = $84.50 + $15.21 = $99.71

2. X is What Percent of Y?

Given two numbers, find the percentage relationship.

Formula:

Percentage = (X ÷ Y) × 100

Example:

25 is what percent of 200?
= (25 ÷ 200) × 100
= 0.125 × 100
= 12.5%

Real-world use: You scored 42 out of 50 on a test.

42 ÷ 50 × 100 = 84%

3. Percentage Increase / Decrease

Find the percentage change from an old value to a new value.

Formula:

Change = ((New - Old) ÷ |Old|) × 100

Example (increase):

Salary went from $50,000 to $55,000
= ((55000 - 50000) ÷ 50000) × 100
= (5000 ÷ 50000) × 100
= 10% increase

Example (decrease):

Price dropped from $80 to $60
= ((60 - 80) ÷ 80) × 100
= (-20 ÷ 80) × 100
= -25% (25% decrease)

4. Add / Subtract Percentage

Add a percentage to a number (e.g., adding tax) or subtract (e.g., applying a discount).

Formula (add tax):

Total = Price × (1 + TaxRate ÷ 100)

Example:

Item costs $120, sales tax is 8%
Total = 120 × (1 + 0.08) = 120 × 1.08 = $129.60

Formula (apply discount):

Discounted = Price × (1 - Discount ÷ 100)

Example:

Jacket is $85 with 30% off
Sale price = 85 × (1 - 0.30) = 85 × 0.70 = $59.50
You save = $85 - $59.50 = $25.50

Common Percentage Scenarios

Shopping Discounts

Financial Calculations

Compound interest simplified:

If you invest $10,000 at 7% annual return:

Mortgage down payment:

Home price: $350,000
Down payment: 20% = $70,000
Loan amount: $280,000

Academic Grades

Business Metrics

Profit Margin:

Revenue: $500,000
Cost: $350,000
Profit: $150,000
Margin: 150000 ÷ 500000 × 100 = 30%

Growth Rate:

Q1 sales: $100,000
Q2 sales: $130,000
Growth: ((130000 - 100000) ÷ 100000) × 100 = 30%

How to Use Our Calculator

Visit our Percentage Calculator.

Step 1: Choose your calculation mode:

Step 2: Enter your numbers into the input fields.

Step 3: See the result instantly — no button to click. The tool updates in real time as you type.

Tips for Manual Calculations

Quick Mental Math

Combine these for other percentages:

15% of 200 = 10% of 200 + 5% of 200 = 20 + 10 = 30
35% of 80 = 25% of 80 + 10% of 80 = 20 + 8 = 28

Fraction Equivalents

FAQ

What's the difference between percentage and percentage points? A percentage point is the arithmetic difference between two percentages. If a rate goes from 5% to 7%, that's a 2 percentage point increase, but a 40% increase in the rate itself.

How do I calculate a reverse percentage? If you know the result and the percentage, find the original. Example: You paid $75 after a 25% discount. Original = 75 ÷ (1 - 0.25) = 75 ÷ 0.75 = $100.

Can I use decimals in percentages? Yes — our calculator accepts decimals. 7.5% works the same as 7.5.

Is there a limit on how large the numbers can be? The calculator handles numbers up to millions with precision up to 4 decimal places.

What is a percentage error? It compares an approximate value to an exact value: |(Approximate - Exact) ÷ Exact| × 100. Used in science, engineering, and statistics.