About Smart Financial Calc
Smart Financial Calc is a free collection of calculators for money, math, dates and times, unit conversions, home projects and fitness estimates. Each calculator shows the formula it uses, the steps worked with your own numbers, and the assumptions behind the result.
What the site is
- Calculators that run in your browser. The numbers you type are processed on your device and are not sent to the site or to anyone else, unless you create and open a share link.
- An explanation with every calculator: what it answers, how to use it, the formula, a worked example, how to read the result, its assumptions and limits, and common mistakes, with links to the sources the formulas come from.
- Free to use, with no account, sign-up or email address needed.
What the site is not
Smart Financial Calc is not a lender, bank, broker, insurer, tax preparer, financial adviser or healthcare provider. Results are educational estimates based on the numbers and assumptions you enter. They are not quotes, offers, lending decisions, tax filings, or financial, legal or medical advice. The disclaimer sets out the limits for each kind of calculator.
Who runs it
Smart Financial Calc is an independent website, operated by an individual in New York, United States. Pages are published under the site’s name rather than attributed to individual authors, and the methodology page describes exactly how they are produced, including the use of AI assistance.
How the calculators are built
- Formulas from cited sources. Each calculator lists the sources its formulas and factual statements rely on, such as regulators, standards bodies, official health agencies, peer-reviewed papers and standard textbooks.
- Calculated on your device. The math runs in your browser, so results appear as you type and your inputs stay with you.
- Tested against independent values. Automated tests compare each calculator with expected results worked out separately (by hand, from published worked examples, or with independent software), never by re-running the calculator’s own code. Browser tests also fill in each form and check the results that appear.
Independence
The site has no affiliate links or sponsored content, and no calculator recommends a lender, bank, insurer or any other provider. Where a choice depends on your situation, the explanation sets out the trade-offs and leaves the decision to you.
The home page, calculator pages and guides, except the fitness pages, may show ads served by Google AdSense. Google selects the ads; advertisers have no say in the calculators or in what the pages say. Any ads are labeled “Advertisements” and are kept away from calculator inputs and results. The privacy policy explains how advertising uses data.
Mistakes and questions
If a result looks wrong, please report it on the corrections page, where confirmed corrections are also listed. For anything else, see the contact page.