Percentage Calculator

The Swiss Army Knife of math. Solve percentage change, find values, or calculate discounts instantly.

What is % of ? Answer: 100
is what % of ? Answer: 25%
From to is a change of +50%

Mastering Percentages

Shopping & Sales

Quickly find out how much you'll save. If an item is $80 with a 15% discount, use the first tool to find the savings ($12) and subtract it from the total.

Investment Growth

Use the Percentage Change tool to track your portfolio. Did your stock go from $45 to $52? That’s a 15.5% increase.

Business Margins

Calculate what percentage of your revenue is profit. If you made $1,000 and kept $300, use the second tool to see your 30% margin.

The Science of Percentages

A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%". Percentages are essential in almost every aspect of life, from calculating tax and interest rates to understanding statistics in the news.

Why Percent Change is Tricky

One of the most common mistakes in finance is misunderstanding percentage recovery. If your investment drops by 50%, it doesn't need to grow by 50% to get back to even—it needs to grow by 100%. Our calculator helps you visualize these shifts accurately.

Common Formula

Percentage = (Value / Total) × 100

Percentage FAQ

1. How do I calculate percentage in my head?
A great trick is the 10% rule: find 10% by moving the decimal one place to the left, then double it for 20% or half it for 5%.
2. What is the difference between percentage and percentage points?
If an interest rate goes from 10% to 12%, it has increased by 2 percentage points, but it has increased by 20 percent.
3. How do I calculate a discount?
Multiply the original price by the percentage, then divide by 100. Subtract that result from the original price.
4. Can a percentage be over 100?
Yes. A percentage over 100 means the value is greater than the original base. 200% of a number is double that number.
5. How do you find the percentage of two numbers?
Divide the smaller number by the larger number and multiply by 100. For example, 2/5 = 0.4, which is 40%.
6. What is the "is over of" method?
It's a mnemonic: (is / of) = (% / 100). If you know three of these values, you can solve for the fourth.
7. How do I calculate a 15% tip?
Find 10% (move decimal), find half of that (which is 5%), and add them together.
8. Why is zero a problem in percentage math?
You cannot divide by zero. Therefore, you cannot calculate a percentage increase from zero, as the growth would be considered infinite.