Calculators and utilities, with the working shown

A library of calculators, not a pile of pages

A-Z Super Utility is an independent site of free calculators, converters, and browser utilities. The library is deliberately limited. A page is published when the tool does one job and the explanation under it is specific to that job: the formula, a worked example, and the cases where the result misleads. Pages that only repeated another website — song lyrics, news headlines, Wikipedia summaries, catalogues of books, TV, and anime — are not part of the library.

Calculators and file tools run in your browser. Tools that need a live figure, such as weather or exchange rates, send only that query. There is no account.

What You Can Do

• Finance — plan loans and investments with EMI, SIP, mortgage, income tax, and compound interest calculators.
• Health & Fitness — track BMI, calories, BMR, body fat, pregnancy, and sleep with trusted formulas.
• Developer — format JSON, decode JWTs, test regex, and work with colours.
• Image & PDF — convert, compress, merge, and resize files privately in your browser.
• SEO & Text — generate meta tags, sitemaps, and schema, and count, convert, or clean up text.

Read the how-to guides, or the about page for who maintains the library and how corrections are handled.

How These Tools Are Built and Checked

Every calculator here implements a documented, publicly verifiable method — a standard formula, an official specification, or an established convention — and each tool page states which method it uses. Where more than one method exists, the page explains the difference: the BMR calculator uses the Mifflin-St Jeor equation and says why it is preferred over the older Harris-Benedict formula; the loan tools use reducing-balance interest and contrast it with the flat-rate quoting that makes some loans look cheaper than they are; the standard deviation calculator offers both population and sample formulas and explains when each applies.

Just as importantly, each page states what its tool cannot account for. A BMI figure says nothing about body composition. A loan calculation excludes processing fees, insurance and taxes. A seven-day forecast is roughly half as reliable as tomorrow's. A result presented without its limitations is not a useful result, so we publish the limitations alongside the number.

Every tool page shows the date its content was last reviewed, and pages covering material that changes — tax bands, statutory thresholds, platform limits — are checked more often than pages covering arithmetic. If you find an error, please tell us: a calculator that is quietly wrong is far worse than one that does not exist. Our full editorial policy sets out how content is produced, reviewed and corrected, and how advertising is kept separate from it.

Where We Do Not Give Advice

Several tools here touch subjects where being wrong has real consequences. The health calculators produce general estimates from population-level formulas and cannot account for your medical history, medication or circumstances — they are a starting point for a conversation with a doctor or registered dietitian, not a replacement for one. The finance tools perform arithmetic on figures you supply; they do not know your tax position or the terms of any specific product, and nothing here is financial advice. Tax and legal tools reflect general rules that vary by jurisdiction and change over time.

Frequently Asked Questions