Home › Math & Science › Percentage Calculator

Percentage Calculator

Four modes — find any unknown in a percentage problem.

What is X% of Y?

Result
—

X is what % of Y?

Percentage
—

Percentage change from X to Y

% Change
—
Absolute Change —
Direction —

Increase or decrease a number by %

New Value
—
Difference —

How to Use This Calculator

  1. Choose the calculation mode using the tabs at the top.
  2. Enter the known values in the input fields — results update instantly.
  3. Use the example chips to quickly load common scenarios.
  4. Switch between modes to solve different types of percentage problems.
  5. The formula line below each result shows exactly how the answer was calculated.
📋

How to Use This Calculator

1

Select the Calculation Type

Choose from: What is X% of Y, what percent is X of Y, or percentage increase/decrease.

2

Enter Your Values

Type the numbers relevant to your chosen calculation type.

3

Read the Answer

The percentage result or the computed value is displayed instantly.

⚡

Formula & Methodology

X% of Y
Result = (X / 100) × Y
Convert the percentage to a decimal and multiply by the base value.
Percentage of Total
% = (Part / Whole) × 100
Divide the part by the whole and multiply by 100.
Percentage Change
% Change = ((New − Old) / Old) × 100
A positive result indicates an increase; a negative result indicates a decrease.

About this calculation · Accuracy & Methodology

📊

Percentage Calculation Types

TypeQuestionFormulaExample
Find PartWhat is X% of Y?Y × X/10015% of 200 = 30
Find PercentX is what % of Y?(X/Y) × 10030 of 200 = 15%
Find WholeX is Y% of what?X / (Y/100)30 is 15% of 200
% IncreaseFrom X to Y?((Y−X)/X)×10080 to 100 = 25%
% DecreaseFrom X to Y?((X−Y)/X)×100100 to 80 = 20%
📖

Key Terms

Percentage (%) A ratio expressed as a fraction of 100. For example, 45% means 45 out of 100.
Base Value The original or reference number from which a percentage is calculated.
Percentage Increase The amount by which a value has grown, expressed as a percent of the original.
Percentage Decrease The amount by which a value has shrunk, expressed as a percent of the original.
Basis Point (bp) One hundredth of a percentage point (0.01%); used in finance for interest-rate changes.
👥

Real-World Examples

📊

Sale Discount

Input: What is 25% of $80?

Result
$20

$20 — the discount amount; the sale price is $60

📄

Percentages: The Universal Language of Comparison

Why Percentages Are Everywhere

Percentages normalize comparisons across different scales. A 10% return on a $1,000 investment and a 10% return on a $100,000 investment represent the same relative performance despite vastly different dollar amounts. Tax rates, discounts, interest rates, statistical results, and nutritional labels all use percentages because they provide instant, scale-independent context.

Common Percentage Pitfalls

A 50% increase followed by a 50% decrease does not return to the original value—it leaves you at 75% of the starting point. Percentage points and percentages are also frequently confused: if a rate moves from 5% to 8%, that is a 3-percentage-point increase but a 60% relative increase. Being precise about these distinctions is essential in finance, journalism, and data analysis.

❓

Frequently Asked Questions

How do I calculate what percentage one number is of another?+

Divide the part by the whole and multiply by 100. For example, 25 out of 200 equals 25 divided by 200 times 100, which is 12.5 percent. Enter both numbers into the calculator for instant results.

How do I calculate a percentage increase or decrease?+

Subtract the old value from the new value, divide by the old value, and multiply by 100. A price going from 80 to 100 dollars is a 25 percent increase because (100-80)/80 times 100 equals 25.

What is the difference between percentage and percentile?+

A percentage represents a fraction of 100 (e.g., 85%), while a percentile indicates ranking within a distribution (e.g., the 85th percentile means you scored higher than 85% of all test-takers). They measure different things.

How do I find the original price before a discount?+

Divide the discounted price by (1 minus the discount rate). If an item costs 60 dollars after a 25 percent discount, the original price was 60 divided by 0.75, which equals 80 dollars.

Can I calculate percentage of percentage?+

Yes, simply multiply the two percentages together and divide by 100. For example, 20 percent of 50 percent equals (20 times 50) divided by 100, which is 10 percent. This is useful in chained discount and tax calculations.

How do you calculate a percentage?

To find a percentage, divide the part by the whole and multiply by 100. For example, 25 out of 200 is (25/200) x 100 = 12.5%. To find a percentage of a number, multiply the number by the percentage divided by 100.