About financecalc

financecalc is a free website of online calculators for personal finance, health metrics, math, and unit conversion. We publish each tool with the formula or rule it uses, a worked example, and honest limitations so you can judge whether the result fits your situation.

Why this site exists

Many calculator pages show a form and a number with little explanation. That makes it hard to know what the result includes, what it leaves out, or when the method is a poor fit. Our goal is the opposite: every calculator page should help you understand the answer, not only generate it.

Typical questions we aim to answer include: What does a mortgage payment exclude? How does BMI categorize weight? What factor converts pounds to kilograms? What is the difference between percent change and percentage points? You should leave with both a number and context.

How calculators are built

Calculators run in your browser using standard formulas (for example, fixed-rate amortization for mortgages, Mifflin–St Jeor for calorie estimates, and internationally defined conversion factors for length and mass). Inputs stay on your device for the calculation itself; we do not require an account to use the tools.

We organize tools into four categories — Financial, Health, Math, and Conversion — so you can browse by topic. Featured calculators on the home page highlight the tools people open most often. Each calculator also links to related tools in the same category.

Editorial approach

• Original explanations — We write our own how-it-works sections, examples, and FAQs rather than scraping other sites.
• Transparent methods — Formulas and assumptions are stated on the page so you can verify the logic.
• Clear limits — We call out what a tool does not cover (fees, taxes, medical nuance, uncommon units, and so on).
• Estimates only — Results are for planning and education. They are not financial, medical, or professional advice.

Guides and deeper reading

Beyond the interactive tools, we publish practical guides that explain common decisions around mortgages, BMI, percentages, and unit systems. Those articles are meant to be useful on their own, not filler around ads.

Advertising

We may show advertisements on calculator pages that include substantial publisher content. Listing pages such as the home page and category indexes are kept free of ads. See our Privacy Policy for how third-party ad technology may use cookies and similar technologies.

Contact

Questions, corrections, or feedback about a calculator? Visit the Contact page. We welcome reports of errors in formulas, examples, or explanations.