Why Use a Percentage Calculator?
Percentages are everywhere—from shopping discounts and restaurant tips to bank interest rates and tax calculations. While the math is simple, finding the right formula for each scenario can be confusing.
Our All-in-One Percentage Calculator eliminates the guesswork. Whether you are a student checking homework, a shopper calculating a sale price, or a business owner analyzing growth, this tool covers every possible percentage scenario.
Key Features
Basic Percentages
Find X% of Y instantly. Perfect for tips and tax.
Percentage Change
Calculate the increase or decrease between two values (e.g., this year's vs last year's revenue).
Discount Calculator
Enter original price and percent off to see the final price and amount saved.
Reverse Percentage
Find the original number if you only know the final number and the percentage change.
Common Percentage Formulas
Understand the math behind the magic. Here are the formulas we use:
Percentage of Value
(P ÷ 100) × V
Example: 20% of 500 = 0.2 × 500 = 100
Percentage Increase
((New - Old) ÷ Old) × 100
Example: 50 to 75 is a 50% increase.
Percentage Decrease
((Old - New) ÷ Old) × 100
Example: 100 to 80 is a 20% decrease.
Real-World Examples
Tip: The word "percent" comes from the Latin per centum, meaning "by the hundred". It is a way of expressing a number as a fraction of 100.
1. Calculating Tips
If your restaurant bill is $45 and you want to leave a 20% tip, simply calculate: $45 × 0.20 = $9. Your total payment would be $54.
2. Finding Discounts
A shirt originally costs $80 and is on sale for 30% off.
Discount Amount: $80 × 0.30 = $24.
Final Price: $80 - $24 = $56.
3. Stock Market Growth
If you bought a stock at $150 and sold it at $200, what is your return?
Increase = $200 - $150 = $50.
Percentage = ($50 ÷ $150) × 100 = 33.33% Return on Investment (ROI).