Percentage Calculator

What is X% of Y · X is what % of Y · percent change between two numbers.

Stays on your device. This tool runs in your browser — nothing you paste or open ever leaves it. Nothing uploaded, nothing to leak.

Calculation

What is % of ?

is what percent of ?

From to

Help us improve Was this tool useful? Tap a star. Thanks — your rating helps others find it.

Be the first to rate

How to use it

Pick the mode that matches your question, type the two numbers, and the result updates as you type. Each mode shows the formula it used so you can check the working.

Percentage Calculator — TechWhack Score

9.5/10

Privacy 10/10

The maths runs entirely in your browser — nothing you type is sent anywhere or stored.
Speed 10/10

The answer updates the instant you type, with no server round trip.
Features 8/10

Three calculations in one — a percentage of a number, one number as a percent of another, and the increase or decrease between two — each showing its working.
Free 10/10

No sign-up, no limits, no ads in the way.

Verdict: Covers the three percentage questions people actually ask and shows the formula each time, so it teaches as well as answers.

Embed this tool on your site

<iframe src="https://techwhack.com/tools/calculate/percentage-calculator/embed" width="100%" height="440" frameborder="0" loading="lazy"></iframe>
<!-- Powered by TechWhack -->

A percentage calculator works out percentages three ways: what X% of a number is (15% of 80 = 12), what percent one number is of another (12 is 15% of 80), and the percentage increase or decrease between two values. Type the numbers and the answer — with the working — appears instantly in your browser.

The three calculations

What is X% of Y = Y × X ÷ 100 (20% of 150 = 30). X is what percent of Y = X ÷ Y × 100 (30 is 20% of 150). Percentage change from A to B = (B − A) ÷ |A| × 100 — a positive result is an increase, a negative one a decrease (150 → 180 is +20%).

When you need it

Tips, tax and VAT, discounts and sale prices, test and exam scores, commission, tracking a rise or fall in a figure, and working out margins — anywhere a proportion of a number matters.

FAQ

How do I calculate a percentage of a number?Multiply the number by the percentage and divide by 100. For 15% of 80: 80 × 15 ÷ 100 = 12. The “% of a number” mode does this for you.

How do I work out percentage increase or decrease?Subtract the old value from the new one, divide by the old value, and multiply by 100. From 200 to 250 is (250 − 200) ÷ 200 × 100 = 25% increase. A negative answer is a decrease.

How do I find what percent one number is of another?Divide the first number by the second and multiply by 100. 30 out of 120 is 30 ÷ 120 × 100 = 25%.

Is anything I type uploaded?No — every calculation runs in your browser and nothing is sent to a server or stored.