What is X% of Y?

e.g. 15% of 200 = 30

%
of

Result

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X is what % of Y?

e.g. 30 of 150 = 20%

is what % of

Result

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Increase / Decrease

e.g. 50 to 75 = +50% increase

From
To

Result

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Everything runs in your browser. Your numbers never leave your device.

Why Use PercentCraft?

PercentCraft is a free online percentage calculator that answers the three most common percentage questions instantly.

  • Three calculators in one: percentage of a number, ratio to percent, and percentage increase or decrease.
  • Instant results: updates live as you type, with no button to press.
  • Private and secure: 100% client-side JavaScript, no server, no sign-up.
  • Handy extras: Copy Result buttons, Reset All, and dark or light mode.
  • Works everywhere: fast, responsive and accessible on phones, tablets and desktops.

How to Use the Percentage Calculator

Pick the card that matches your question and type your numbers. Results update instantly as you type. Use Copy Result to copy an answer, or Reset All to clear every field. It works for discounts, tips, taxes, grades, price changes and growth rates.

Percentage Formulas Explained

Percentage of a number

Y × X ÷ 100. Example: 15% of 200 = 30.

Ratio as a percentage

X ÷ Y × 100. Example: 30 of 150 = 20%.

Percentage change

(Y − X) ÷ X × 100. Example: 50 to 75 = +50%.

Frequently Asked Questions

How to calculate percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 15% of 200 = 200 × 15 / 100 = 30.

How to calculate percentage increase or decrease?

Subtract the old value from the new value, divide by the old value, then multiply by 100. For example, from 50 to 75: (75 − 50) / 50 × 100 = +50%. A negative result is a decrease.

How do I find what percentage one number is of another?

Divide the part by the whole and multiply by 100. For example, 30 is 30 / 150 × 100 = 20% of 150.

How do I calculate a discount?

Use 'What is X% of Y?' to find the discount amount, then subtract it from the original price. A 20% discount on 80 is 16, so the final price is 64.

How do I convert a ratio to a percent?

Divide the first number by the second and multiply by 100. A ratio of 3:4 is 3 / 4 × 100 = 75%.

Is this percentage calculator free?

Yes. PercentCraft is 100% free, needs no sign-up, and all calculations run locally in your browser so your numbers are never sent to a server.

Is PercentCraft private and secure?

Yes. It is 100% client-side JavaScript with no backend, no accounts and no data uploads. Nothing you type leaves your device.