What Is a Percentage Calculator?

A percentage calculator is a simple mathematical tool that helps you quickly find the relationship between numbers expressed as a percentage. It allows you to determine how one quantity compares to another in terms of parts per hundred. Percentages are widely used in everyday life — from calculating discounts, tax, and interest to tracking progress, profits, and health metrics. The calculator simplifies this by automatically applying the correct formulas, saving you time and reducing the chance of manual error.

How Do You Calculate Percentage?

A percentage is a way of expressing a number as a fraction of 100. It shows how one value compares to another in terms of “parts per hundred.” Calculating a percentage is simple — you divide the part (or portion) by the total amount, then multiply the result by 100.
For example, if you scored 45 out of 60 marks, the percentage is (45 ÷ 60) × 100 = 75%.
Percentages make it easier to compare numbers of different sizes, since everything is scaled to a base of 100. They are widely used in school marks, financial reports, discounts, profits, and data analysis.
Sometimes, you may also reverse the calculation — for instance, to find what number a certain percentage represents (e.g., “What is 20% of 500?” → (20/100) × 500 = 100) or to determine how much one value has increased or decreased compared to another. In short, the percentage formula helps you measure change, proportion, and comparison in a simple and universally understood way.

What is X% of Y?

Example Use cases

1. Calculating a discount (e.g., 20% off ₹500).
2. Estimating tax or tip on a bill.
3. Finding marks or grades in exams when a percentage of total marks is needed.
4. Determining profit or commission percentages in business.

X is what percent of Y?

Example Use cases

1. Finding success rates or conversion percentages.
2. Comparing expenses to income.
3. Checking how much of your goal is completed (e.g., 40 is what percent of 100?).
4. Determining performance growth or change ratios.

What is the percentage increase or decrease from X to Y?

Example Use cases

1. Calculating price changes in products or stocks.
2. Measuring weight loss/gain or fitness progress.
3. Analyzing sales growth or decline in business.
4. Checking population growth, inflation, or other trends.

Why Use a Percentage Calculator?

Doing percentage math by hand can lead to confusion or rounding errors. A percentage calculator:

1. Ensures accuracy and speed.
2. Handles multiple types of percentage problems in one place.
3. Helps students, professionals, and businesses make quick data-based decisions.
4. Improves productivity by automating routine calculations.