How do you calculate a percentage of a number?

To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 is (200 × 15) ÷ 100 = 30. You can also multiply 200 by 0.15 to get the same result.

How do you calculate percentage change between two numbers?

Percentage change from X to Y is calculated as (Y - X) ÷ X × 100. If the result is positive, it is an increase. If negative, it is a decrease. For example, from 80 to 100: (100 - 80) ÷ 80 × 100 = 25% increase.

What is the formula for percentage increase?

The percentage increase formula is ((New Value - Original Value) ÷ Original Value) × 100. This gives you the percentage growth from the original to the new value.

Percentage Calculator

Calculate percentages instantly — no sign-up, no hassle.

Percent (X%)

Total (Y)

▶ How This Calculator Works

This free percentage calculator handles three of the most common percentage calculations you'll encounter in everyday life, school, or business. Each mode uses straightforward mathematical formulas to give you instant, accurate results as you type.

What is X% of Y? — Multiply Y by X and divide by 100. For example, 15% of 200 equals (200 × 15) ÷ 100 = 30. This is useful for calculating tips, sales discounts, taxes, or any scenario where you need to find a percentage of a total amount.

X is what % of Y? — Divide X by Y and multiply by 100. For example, 30 is what percent of 150? (30 ÷ 150) × 100 = 20%. Use this when you know a part and whole and want to understand the proportion — like calculating your score on a test or figuring out what portion of your budget went to groceries.

Percentage Change — Calculate how much a value has increased or decreased as a percentage. Formula: ((New - Old) ÷ Old) × 100. An increase from 80 to 100 is a 25% increase. A decrease from 100 to 80 is a 20% decrease. This mode is particularly useful for tracking price changes, analyzing data trends, or comparing performance over time.

All results update instantly as you type — no need to press Enter or wait for a button. The animated result counter and progress bar give you a visual sense of the magnitude of your calculation, making the numbers easier to interpret at a glance.

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Home / Everyday / Percentage Calculator · Last updated May 21, 2026 · Expert reviewed

How to use this calculator for a real decision

The percentage calculator supports three common operations: find what percent X is of Y, find X% of Y, and find the percentage change from one number to another. Use it for quick calculations like tip amounts, discount savings, grade scores, tax estimates, investment returns, or sale comparisons. It is the Swiss Army knife of everyday math — anytime you need to convert a fraction into a percentage or figure out how much something changed in relative terms.

Worked example

A store is running a 25% off sale on a $240 jacket. Enter 25% of 240 to get $60 off, making the price $180. Separately, last month you earned $3,200 and this month $3,680. Compute the percentage change: (3680-3200)/3200 × 100 = 15% increase. If a test has 85 questions and you answered 68 correctly, what percent is that? 68/85 × 100 = 80%. Three modes, one calculator.

Common mistakes to avoid

Confusing percentage point with percent change: A rate going from 4% to 5% is a 1 percentage point increase but a 25% increase. These are not the same.
Applying percentage changes sequentially without compounding: A 20% discount followed by an additional 10% off is 28% total, not 30%. The second discount applies to the reduced price.
Using the wrong base for percentage change: Going from 100 to 150 is a 50% increase, but going from 150 back to 100 is a 33% decrease. Always use the original number as the base.
Mixing decimals and percentages: 0.5 and 50% are the same value, but entering one where the other is expected gives wrong results. This calculator makes the distinction clear.

Key terminology

Percentagea fraction expressed as parts per hundred, denoted by the % symbol

Percentage pointthe arithmetic difference between two percentages, not a relative change

Percentage changethe relative difference between two values: (new - old) / old × 100

Base valuethe number that represents 100% in a percentage calculation

Compound percentagemultiple percentage changes applied in sequence, where each applies to the result of the previous

Methodology and sources

Three formulas: (X/Y) × 100 for what percent, (X × Y/100) for X% of Y, and ((new - old) / old) × 100 for percentage change. All results are rounded to 2 decimal places.

Frequently asked questions

What is the difference between percentage and percentage point?

If a rate rises from 4% to 6%, that is a 2 percentage point increase but a 50% increase. The first is absolute, the second is relative.

How do I calculate a percentage of a percentage?

Multiply the percentages: 50% of 20% = 0.50 × 0.20 = 0.10 = 10%. Enter the base percentage as Y and the desired percentage as X.

Why does percentage change give different results going up vs down?

Because the base value changes. A $10 increase from $100 is 10%, but from $110 is 9.1%. Always use the starting value as the base.

How do I calculate percentage increase for a raise?

Percentage change mode: enter old salary as first number, new salary as second. The result tells you the raise percentage.