Percentage Calculator — Free Online Tool
Solve any percentage problem — % of, % change, % difference. · No signup · Works on mobile
100% private: your data is processed in your browser. Nothing is uploaded to our servers.
How to use the percentage calculator
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Pick the question type — e.g. "What is X% of Y?" or "Percentage change".
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Enter your two numbers in the highlighted fields.
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Read the answer instantly, with the formula shown so you can learn it.
What does this tool do?
This free percentage calculator solves every common percentage problem instantly: what is X% of Y, what percent is X of Y, percentage increase or decrease between two numbers, and adding or subtracting a percentage from a value. Type your numbers and the answer appears as you type.
How does the percentage calculator work?
Each mode applies the matching formula: X% of Y = X÷100×Y; "X is what % of Y" = X÷Y×100; percentage change = (new−old)÷old×100. All calculations run locally in your browser with results rounded to a sensible number of decimals.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. For 15% of 240: 240 × 0.15 = 36. A mental shortcut: find 10% (move the decimal one place left → 24), then add half of that for 5% (12), giving 36.
How do I work out percentage increase between two numbers?
Subtract the old value from the new, divide by the old value, then multiply by 100. If rent rose from ₹18,000 to ₹19,800: (19800−18000) ÷ 18000 × 100 = 10% increase. Note that a 10% increase followed by a 10% decrease does not return to the original number.
Is the percentage calculator really free?
Yes — 100% free with no hidden charges, trial limits, or premium tiers for core features. You don't need to create an account or enter an email address. The site is supported by non-intrusive display ads, which keeps every tool free for everyone.
Is my data private when using the percentage calculator?
Completely. The percentage calculator runs entirely in your browser using JavaScript — nothing you type or upload is sent to our servers. When you close the tab, your data is gone. This makes it safe for confidential documents, financial figures, and personal information.
Does the percentage calculator work on mobile phones?
Yes. The percentage calculator is built mobile-first and works on any phone or tablet with a modern browser — iPhone (Safari), Android (Chrome), and everything in between. The layout adapts to small screens, so buttons and inputs stay easy to tap on a 375px-wide display.
Do I need to install anything to use the percentage calculator?
No. The percentage calculator works directly in your web browser — no downloads, no extensions, no signup. Just open the page, use the tool, and get your result instantly. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.