Editorial Policy & Methodology

UseACalculator.com is independently built and operated by its founder, Samir Messaoudi, a software engineer. He designs and codes every calculator and writes every guide. The site is not affiliated with any bank, lender, insurance company, broker, or healthcare provider, has no investors, and accepts no payment for rankings, recommendations, or calculator results.

Calculators use established, verifiable methods rather than proprietary models. Financial tools are built on standard practices: the 28/36 debt-to-income framework used in conventional mortgage lending, standard amortization mathematics, published IRS figures for tax-related estimates, and widely used planning conventions such as safe-withdrawal and emergency-fund guidelines. Health tools use published formulas and guidelines (for example BMI, BMR/TDEE equations, and USDA dietary reference values). Math and conversion tools implement exact, textbook definitions.

Each calculator page states its methodology, key assumptions, and limitations directly in the interface — including worked examples where they help — so the math can be checked rather than taken on faith.

Every result on this site is an estimate driven by the inputs you provide and the stated assumptions. Real-world outcomes depend on variables no calculator can see: your full financial picture, local costs, underwriting decisions, health history, and more. Nothing here is financial, legal, tax, or medical advice, and no tool creates a professional relationship. For consequential decisions, use these tools to get oriented — then confirm with a qualified professional.

Tools that depend on figures that change over time — tax parameters, contribution limits, rate assumptions, guideline values — are reviewed and updated when the underlying standards change. Guides display their published and last-updated dates, and calculator methodology notes are revised alongside the tools they describe. If a dated figure looks stale, treat that as a reason to double-check it — and ideally to report it.

Errors get fixed, not defended. If you find a mistake in a formula, an assumption, a worked example, or a guide, report it through the contact page. Confirmed errors are corrected in the tool or article itself, and material corrections update the page's last-updated date.

UseACalculator.com is free to use and does not require an account. The site may display advertising (such as Google AdSense). Advertisers have no influence over calculator formulas, results, or editorial content, and no calculator output is ever altered for commercial reasons. The site does not sell user data, and calculator inputs are processed in your browser.

Questions about this policy, a specific methodology, or a correction: get in touch. For more about the site's purpose, see the About page.