What This Site Is
Basic Free Tools is a collection of 490+ browser-based calculators, converters, and utilities. Every tool runs entirely in your browser. No data is sent to a server. No account is needed.
The site covers finance calculators, developer utilities, health tools, unit converters, text processors, engineering calculators, and more -- organized across 19 categories. New tools are added regularly.
Why It Exists
Most online tool sites are slow, filled with intrusive ads, or require sign-ups just to use a simple calculator. Basic Free Tools was built as the opposite: fast, private, and respectful of your time.
The goal is simple -- provide genuinely useful tools that solve one problem per page, instantly, without wasting your attention on anything else.
Who Built This
Basic Free Tools is created and maintained by Marc Eisenhardt, based in Gaertringen, Germany.
The site is built as a static site using Eleventy and hosted on Cloudflare Pages. This architecture means pages load fast, there are no databases storing your data, and the site works reliably even under heavy traffic.
How Tools Are Built
Each tool is hand-crafted with accurate formulas and clear explanations. Where applicable, the underlying formula or algorithm is documented directly on the tool page so you can verify the math yourself.
Tools are built for correctness first and convenience second. That said, they are intended for informational and educational purposes -- not as substitutes for professional financial, medical, or legal advice. See our disclaimer for details.
If you spot an error or have a suggestion, every page has a feedback button, or you can contact us directly. We read every message.
Privacy by Architecture
This is not just a privacy policy promise -- it is a technical fact. Tools run JavaScript in your browser. Your inputs never leave your device. There are no analytics cookies, no tracking pixels, no third-party scripts watching what you do.
Read the full privacy policy for details on what minimal data our hosting infrastructure processes.
Get in Touch
Questions, suggestions, or bug reports are welcome. Visit the contact page or email [email protected].
For legal and business information, see the imprint.