About tounits.com

Last updated: July 2025

What we do

tounits.com is a free unit conversion tool and reference site. Enter a value with units (e.g. 3 feet, 100 kg, 72 F) and see instant conversions to compatible units across length, mass, temperature, volume, area, and more. We also publish in-depth conversion guides for common pairs like pounds-to-kg and Celsius-to-Fahrenheit.

Who we are

tounits.com is operated as an independent utility site focused on accurate, fast conversions. We combine a browser-based converter (shareable links, offline-capable after first visit) with editorial guides that explain when and why conversions matter—not just the formula.

Accuracy and sources

Conversion factors in the app and guides follow internationally recognized definitions, including:

• NIST Special Publication 811 (Guide for the Use of the International System of Units)
• BIPM SI Brochure (International System of Units)
• US customary and imperial definitions where applicable (e.g. international inch = 2.54 cm exactly; US gallon = 231 in³)

We distinguish US gallons from UK imperial gallons, fluid ounces from mass ounces, and statute miles from nautical miles—common sources of real-world error.

Editorial process

Each guide includes worked examples, context for everyday use, common mistakes, and linked references. Guides show a “Last updated” date. If you find an error, email [email protected] with the page URL and source.

Privacy and analytics

Theme preference, recent queries, and cookie consent are stored in your browser. We do not require an account. With your consent, we use privacy-focused analytics (Matomo) and may show ads via Google AdSense. Details are in our Privacy Policy.

Disclaimer

Conversions are for general reference. Verify results before use in engineering, medical, legal, or financial decisions. See our Terms of Service.

Contact

General questions: [email protected] · Corrections: [email protected] · See the Contact page for privacy and accessibility addresses.