Math

Percentage Calculator

Solve common percentage phrases, percentage change, and reverse-percentage questions.

Inputs

Results update as you edit.

Question

Result

Results update as the calculator inputs change.

150

Decimal form

0.2

How to Calculate Percentages

Percent Means Per 100

A percentage converts a ratio into parts per hundred.

Choose the Question

Different percentage questions rearrange the same relationship between percent, base, and result.

Change

Percentage change compares the difference between old and new values to the original value.

How to Read Percentage Problems

Most percentage questions are variations of part, whole, and rate. Identifying which value is unknown makes the calculation straightforward.

What Affects Percentage Results?

Base Value

The base is the whole amount the percentage applies to.

Rate

The percent rate is converted to a decimal for calculation.

Part

The part is the amount represented by the percentage.

Increase

Percent increase compares gain to the original value.

Decrease

Percent decrease compares loss to the original value.

Reverse Percent

Reverse calculations find the original value before a percent change.

Common Percentage Uses

Discounts

Calculate sale prices and markdowns.

Tax and Tips

Estimate added percentage costs.

Growth Rates

Compare before-and-after values with percentage change.

Frequently Asked Questions

How do I find X percent of Y?

Convert X to a decimal by dividing by 100, then multiply by Y.

How do I calculate percentage change?

Subtract old value from new value, divide by old value, then multiply by 100.

What is a reverse percentage?

It finds the original amount before a percentage increase or decrease was applied.

Why are percentages useful?

They normalize comparisons so different-sized amounts can be compared on the same scale.

Can a percentage be over 100?

Yes. A value can be more than 100 percent of another value, or grow by more than 100 percent.