How do I calculate a percentage of a number?

To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30. This formula works for any percentage and any number, including decimals.

How do I find what percentage one number is of another?

Divide the part by the whole and multiply by 100. For example, 30 is what percent of 200? Answer: (30 ÷ 200) × 100 = 15%. This tells you the proportion of the part relative to the whole expressed as a percentage.

How do I calculate percentage change?

Percentage change = ((New Value - Old Value) / Old Value) × 100. A positive result means an increase, while a negative result means a decrease. For example, going from 80 to 100 is a ((100-80)/80) × 100 = 25% increase.

What is the difference between percentage and percentile?

A percentage is a fraction of 100 (e.g., 85% means 85 out of 100). A percentile indicates the value below which a given percentage of observations fall in a dataset. For example, the 90th percentile means 90% of data points are below that value.

Free Percentage Calculator — Quick & Easy Math Tool

Percentage Calculator

What is X% of Y?

Percentage (%)

Number

Result

X is what % of Y?

Number (X)

is what % of

Number (Y)

Result

15%

Percentage Change from X to Y

From (Old Value)

To (New Value)

Change

25% increase

How to Calculate Percentages

Percentages are one of the most common mathematical concepts used in everyday life, from calculating tips and discounts to understanding statistics and financial data. A percentage represents a fraction of 100 and is denoted by the symbol %. For example, 25% means 25 out of every 100.

This calculator handles three essential percentage calculations. The first finds a specific percentage of a number using the formula: Result = (Percentage × Number) ÷ 100. The second determines what percentage one number is of another: Percentage = (Part ÷ Whole) × 100. The third calculates the percentage change between two values: Change = ((New − Old) ÷ Old) × 100.

Understanding percentages is crucial for many real-world applications. Sales tax calculations, grade computations, investment returns, and statistical analysis all rely on percentage math. When comparing values of different magnitudes, percentages provide a standardized way to express proportions. A 10% increase on 50 is 5, while a 10% increase on 1,000 is 100, both represent the same proportional growth. This calculator handles all inputs including negative numbers and decimals, giving you instant results as you type.

Formula

1. Percentage of a number:

Result = (Percentage × Number) / 100

2. What percentage is X of Y:

Percentage = (X / Y) × 100

3. Percentage change:

Change% = ((New Value − Old Value) / Old Value) × 100

Example Calculation

Scenario 1: What is 15% of 200?

Result = (15 × 200) / 100 = 30

Scenario 2: 45 is what percent of 180?

Percentage = (45 / 180) × 100 = 25%

Scenario 3: Price went from $80 to $100. What is the percentage change?

Change = ((100 − 80) / 80) × 100 = 25% increase