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Percentage Calculator

X% of Y · what percent · % change
✓ No sign-up % 3 calculators ⚡ Updates as you type
15% of 200 is
30

Three of the most-searched percentage calculations in one place — updates instantly as you type, no "calculate" button needed.

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What can this calculator do?

Percentage questions come in a few common shapes: "what is 15% of 200?", "30 is what percent of 200?", and "what's the percentage change from 80 to 100?" This tool covers all three, switchable from the tabs above, and updates the answer live as you type.

How to use it

  • Pick the calculation you need from the tabs.
  • Type your two numbers — there's no separate "calculate" step, the answer updates instantly.
  • For % change, a positive result means an increase and a negative result means a decrease.

Good to know

Percentage change is calculated as (new − old) ÷ old × 100. This is different from a percentage point difference — going from 40% to 50% is a 10 percentage point increase, but a 25% relative increase. Use whichever framing matches what you're trying to communicate.

Worked example

Your favourite jacket normally costs $85 and is 30% off. What do you actually pay? Discount = 30% of 85 = 0.30 × 85 = $25.50 Sale price = 85 − 25.50 = $59.50 Enter 30 and 85 on the "X% of Y" tab to get the $25.50 discount amount, then subtract it from the original price yourself.

Frequently asked questions

How do I calculate a discount, like 20% off $50?

Use the "X% of Y" tab: enter 20 as the percent and 50 as the value, which gives you $10 — that's the amount taken off. Subtract that from the original price ($50 minus $10) to get the final sale price of $40.

What's the difference between percentage change and percentage points?

Percentage change is a relative measure — going from 40% to 50% is a 25% relative increase, because (50 minus 40) divided by 40, times 100, equals 25%. A percentage point difference is the plain subtraction — 50% minus 40% equals 10 percentage points. They answer different questions, and mixing them up is one of the most common statistics mistakes in news reporting.

How do I work out what percentage one number is of another?

Use the "X is what % of Y" tab. For example, if you scored 42 out of 60 on a test, enter 42 as the value and 60 as the total — the tool shows 70%, calculated as 42 divided by 60, times 100.

Can this calculate a tip?

Yes, indirectly — a tip is just a percentage of a bill. To tip 18% on a $64 bill, use the "X% of Y" tab with 18 as the percent and 64 as the value, which gives you $11.52 as the tip amount.

Why is my percentage change showing a negative number?

A negative result means the value decreased — for example, going from 100 to 80 gives a result of minus 20%, a 20% decrease. The tool labels it "decrease" automatically whenever the result is negative, so the minus sign and the label always agree.

About & privacy

Every calculation happens locally as you type — your numbers are never sent to or stored on our servers. It's one of Convertly's free, ad-supported calculators; see the full privacy policy for details.