Percentage Calculator
Instantly calculate percentages, find the percentage change between two numbers, or see what percent of a number another value is.
How to Calculate Percentages
Percentages are a core part of everyday math, used for everything from figuring out a tip at a restaurant to analyzing financial growth. This calculator simplifies the process by offering three distinct tools.
1. Find the Percentage of a Number
To calculate a percentage of a number, you simply multiply the base number by the percentage fraction.
Example: What is 20% of 150?
- Convert 20% to a decimal: 20 / 100 = 0.2
- Multiply by 150: 0.2 × 150 = 30
2. Find What Percentage One Number Is of Another
This mode answers questions like "50 is what percent of 200?". It's useful for calculating test scores or completion rates.
Example: 50 is what % of 200?
- Divide the part by the whole: 50 / 200 = 0.25
- Multiply by 100 to get the percentage: 0.25 × 100 = 25%
3. Calculate Percentage Increase or Decrease
Use this to find the relative change between two values over time.
Example: A price goes from $50 to $60.
- Find the difference: 60 - 50 = 10
- Divide by the original value: 10 / 50 = 0.2
- Multiply by 100: 0.2 × 100 = 20% Increase
Frequently Asked Questions
What is the formula for percentage?
The basic formula is P% * X = Y, where P is the percentage, X is the base number, and Y is the result. To find the percentage itself, use (Part/Whole) * 100.
How do I calculate a 20% tip?
To calculate a 20% typical tip, move the decimal point of your bill one place to the left to get 10%, then double that number. For a $50 bill, 10% is $5, so 20% is $10.
Is this calculator accurate?
Yes, our calculator uses precise standard mathematical floating-point arithmetic. It is suitable for academic, financial, and daily use.