Calculators & Time

Percentage Calculator

Switch between four common percentage calculations — no more guessing which formula applies to your specific question.

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Percentage (X)

Value (Y)

Percentage Calculation Methods

Percentages express a proportion as a fraction of 100. Mastering the four common percentage calculation patterns covers the vast majority of real-world use cases.

X% of Y — the most common

Used for discounts, tax calculations, tips, and commission. Formula: (X ÷ 100) × Y. Example: 20% of 85 = 17. A 20% discount on a $85 item saves you $17.

X is what % of Y

Used for score calculations, market share analysis, and survey interpretation. Formula: (X ÷ Y) × 100. Example: 45 is what % of 180? Answer: 25%. You scored 25% of the available marks.

Percentage change

Used for growth rates, inflation, stock returns, and A/B test result comparison. Formula: ((New − Old) ÷ Old) × 100. A positive result is an increase; negative is a decrease. Example: price changed from $80 to $100 → +25% change.

Increase/decrease by percentage

Used for applying raises, markups, and discounts. Increase formula: Value × (1 + P/100). Decrease formula: Value × (1 − P/100). Example: $500 increased by 15% = $575; decreased by 15% = $425.

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How it works

Three steps, no setup

Pick a calculation mode

Percentage of a number, what percent one value is of another, percent change, or adding a percent.

Enter your values

The result updates instantly as you type.

Copy the answer

Useful for discounts, tips, growth rates, and grading.

Common questions

Frequently asked questions

How is percentage change calculated?

It uses (new value − old value) ÷ old value × 100, correctly showing a negative result for a decrease.

What is the difference between "percent of" and "percent change"?

"Percent of" finds a portion of a fixed number, while "percent change" compares two different values over time to show growth or decline.

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Calculators & Time

Percentage Calculator

Percentage Calculation Methods

X% of Y — the most common

X is what % of Y

Percentage change

Increase/decrease by percentage

Three steps, no setup

Pick a calculation mode

Enter your values

Copy the answer

Frequently asked questions

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Percentage Calculation Methods

X% of Y — the most common

X is what % of Y

Percentage change

Increase/decrease by percentage