Breezy Tools

Percentage Calculator

Calculate percentages, percentage change, and what percent one number is of another.

What is X% of Y?
What is% of?
X is what % of Y?
is what % of?
Percentage Change
Fromto

How to Use Percentage Calculator

  1. 1

    Choose a calculation mode

    Select from three modes: calculate a percentage of a number, find what percentage one number is of another, or calculate percentage change between two values.

  2. 2

    Enter your numbers

    Fill in the input fields for your chosen mode. The tool accepts whole numbers and decimals.

  3. 3

    View the result

    The answer is calculated and displayed instantly as you type — no need to press a calculate button.

Key Features

Three Calculation Modes

Calculate "X% of Y", "X is what % of Y", and "percentage change from X to Y" — covering all common percentage needs.

Instant Results

Answers update in real time as you type numbers, so you can quickly try different values.

Decimal Precision

Results are shown with appropriate decimal places for accuracy, whether you are working with small fractions or large numbers.

Clean Interface

A simple, focused layout makes it easy to find the calculation mode you need without confusion.

Common Use Cases

  • Shopping Discounts

    Calculate how much you save when an item is 20% off, or figure out the final price after a percentage discount.

  • Grade Calculations

    Determine what percentage score you received on a test — for example, 42 correct out of 50 questions.

  • Business Metrics

    Calculate percentage change in revenue, growth rates, profit margins, or conversion rates for reports and dashboards.

  • Tip Calculations

    Quickly figure out a 15%, 18%, or 20% tip on a restaurant bill without mental math.

Frequently Asked Questions

How do I calculate a percentage of a number?▾

Multiply the number by the percentage and divide by 100. For example, 25% of 200 = (200 × 25) / 100 = 50. The tool does this for you automatically.

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 % of 120? Answer: (30 / 120) × 100 = 25%.

How is percentage change calculated?▾

Percentage change = ((new value − old value) / old value) × 100. A positive result means an increase; negative means a decrease.

Can I use negative numbers?▾

Yes. The tool handles negative numbers correctly, which is useful for calculating percentage change when values decrease.