About & Methodology
Calculator Hub is a free collection of calculators, unit converters and tools built to give fast, correct answers in your own language. This page explains how the numbers are produced, how we keep them accurate, and how your privacy is protected.
How the calculations work
Every calculator is a small, self-contained formula that runs entirely in your browser using JavaScript double-precision arithmetic (the IEEE 754 standard used by virtually all software). There is no server round-trip, so results appear instantly as you type.
Each formula is defined once and reused across every language, so the German, Japanese and Korean versions of a calculator all compute exactly the same numbers — only the words around them change.
How we keep results accurate
- Every formula ships with a suite of automated test cases checking known inputs against known answers; the site cannot be published unless all of them pass.
- Unit conversions use exact international definitions (for example 1 inch = 0.0254 m, 1 pound = 0.45359237 kg), not rounded approximations.
- Money figures avoid floating-point drift, and results are cleaned to a sensible number of significant digits so 0.1 + 0.2 shows 0.3.
- Formulas that depend on standards — BMI bands, the Mifflin-St Jeor equation, amortization — follow the published, widely used definitions, with the method explained on each page.
Your privacy
Everything you type stays on your device. Calculations run locally in your browser and nothing you enter is uploaded to or stored on a server. Shareable links encode your inputs in the URL only when you choose to copy or share them.
The site shows advertising to remain free; ads are provided by Google and follow their standard privacy practices.
Sources & standards
- SI unit definitions — International Bureau of Weights and Measures (BIPM).
- Body Mass Index categories — World Health Organization (WHO), with Asian-Pacific cut-offs noted.
- Resting metabolic rate — the Mifflin-St Jeor equation.
- Imperial/US customary units — exact conversions defined against the metre and kilogram.
Languages & availability
The hub is available in nine languages — English, 한국어, 日本語, Deutsch, Français, Español, Português, Italiano and Bahasa Indonesia — with a language switcher on every page. Content that is not yet translated links to that language's home so you can always continue in your own language.
It is a Progressive Web App: you can install it and use the calculators offline once visited.
A note on trust
These tools are provided for general information and education. They are accurate for their stated method, but they are not a substitute for professional advice on medical, financial, legal or engineering decisions. For anything important, confirm the figures with a qualified professional or an official source.