What is X% of Y?

% of = —

X is what percent of Y?

is — of

Percentage change from X to Y

from to = —

🔒 Runs entirely in your browser.

Using an AI agent or a script? Call this tool as an API

AI agents and scripts can call this tool directly, to check their work or look something up, and get JSON back with the same answer this page gives. No key needed.

GET https://digitalgreenhouse.com.au/api/tools/percentage-calculator?x=15&y=80
  • x — number, required. First number.
  • y — number, required. Second number.

The API answers from our server, and our code doesn’t store what you send. Fair-use limits apply. API guide · all endpoints (JSON) · OpenAPI

Percentages, plainly

“Per cent” just means “per hundred”. To find X% of Y, multiply Y by X and divide by 100. To see what percent X is of Y, divide X by Y and multiply by 100. And a percentage change is the difference between two numbers as a proportion of the starting number — a price moving from $100 to $150 is a 50% increase. These three cover almost every percentage question that comes up in real life: discounts, tips, mark-ups, results, and growth.

What’s the difference between percent and percentage points?
If a rate rises from 5% to 7%, that’s a 2 percentage point rise but a 40% increase in the rate itself. This tool shows the percentage change.
Need to add or remove GST instead?
That’s a fixed 10% in Australia — use the dedicated GST calculator.

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