Percentage Calculator

Solve percentage problems quickly with this percentage calculator for percent of a number, what percent one value is of another, and percentage increase or decrease.

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Calculation Type

First Value

Percentage (for mode 1) or Part/Original value

Second Value

Number (for mode 1) or Whole/New value

How to Use This Percentage Calculator

A good percentage calculator saves time because percentages show up everywhere: discounts, exam scores, tips, margins, tax, inflation, and price changes. Instead of switching formulas in your head, this calculator gives you three common percentage modes in one place so you can move from question to answer faster.

Choose the mode that matches the question you are trying to solve. If you want to know a share of a number, enter the percentage and the base value. If you want to know what percent one value is of another, enter the part and the whole. For percentage change, enter the original value first and the new value second.

Reading the Result

Each mode is aimed at a different type of decision. Percent of a number is useful for tax, commission, and sale calculations. What percent is useful for marks, ratios, and performance benchmarks. Percentage change is best when you need to describe movement over time, such as revenue growth, weight loss, bill increases, or market moves.

When This Calculator Is Most Useful

This calculator is most helpful when speed and accuracy matter more than mental maths. It is also useful for checking whether a figure sounds plausible before you act on it. Percentage errors are common because people often mix up the base number, the part, and the amount of change, especially when values move both up and down over time.

Practical Tips

When you are calculating change, always start from the original value, not the new one. When you are finding a percentage of a number, remember that 10 percent is just one-tenth, which can help you sanity-check the output. If the result looks surprisingly large, double-check that you entered a whole number percentage rather than a decimal.

Formula

Percent of a number = (percentage / 100) x value. What percent = (part / whole) x 100. Percentage change = ((new - original) / original) x 100.

Frequently Asked Questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply it by the base number. For example, 15 percent of 200 is 0.15 x 200, which equals 30. The calculator handles that automatically when you choose the first mode.

What is the difference between percentage change and percentage points?

Percentage change measures the relative movement between two numbers. Percentage points describe the direct difference between two percentage values, such as moving from 5 percent to 7 percent, which is a rise of 2 percentage points.

Why can percentage decreases be more than 100 percent?

In most real-world cases they cannot, because a value cannot fall below zero. If you are seeing a drop greater than 100 percent, it usually means the numbers were entered in the wrong order or the original figure was not the true starting value.

Can I use this calculator for discounts and markups?

Yes. Discounts use the percent-of-number mode to work out the amount removed from the original price. Markups and price growth are usually best handled with the percentage change mode.