Percent Calculator

Four calculation modes for every type of percent problem. Find the part, the percent, the whole, or the percent change between two values. Each answer comes with a 100-grid, bar model, and step-by-step solution.

What is ___% of ___?

Percent

%

of

Whole

Try an example

Answer

12 (15% of 80)

15% shaded

Bar Model

Step-by-Step Solution

1

\text{Part} = \frac{\text{Percent}}{100} \times \text{Whole}

2

\text{Part} = \frac{15}{100} \times 80

3

\text{Part} = 0.15 \times 80 = 12

Reference Guide

Three Types of Percent Problems

Find the part

"What is 15% of 80?" Use $\text{Part} = \frac{\%}{100} \times \text{Whole}$

Find the percent

"12 is what percent of 50?" Use $\% = \frac{\text{Part}}{\text{Whole}} \times 100$

Find the whole

"30 is 25% of what?" Use $\text{Whole} = \frac{\text{Part}}{\% \div 100}$

Percent Change

Percent change tells you how much a value increased or decreased relative to its original size.

\text{\% change} = \frac{\text{New} - \text{Old}}{\text{Old}} \times 100

A positive result means an increase. A negative result means a decrease. For example, going from 40 to 50 is a 25% increase.

Real-World Uses

Sales tax and tips

A 20% tip on a $65 meal: find 20% of 65 = $13.

Discounts

25% off a $60 item: find 25% of 60 = $15 discount. Sale price = $60 - $15 = $45.

Grades

85 correct out of 100 questions: 85 is what % of 100? Answer: 85%.

The Proportion Method

Every percent problem can be set up as a proportion with "is" over "of" equals "percent" over 100.

\frac{\text{Part}}{\text{Whole}} = \frac{\text{Percent}}{100}

Fill in any two values and cross-multiply to find the third. This single setup works for all three types of percent problems.