About SandSpan

SandSpan is a free, ad-supported unit converter built for everyone — students, engineers, cooks, scientists, travellers and anyone who needs an answer fast.

Our mission

Unit conversion sits at the bottom of every workflow yet rarely deserves the friction it gets. SandSpan exists to make that one part of your day instant: type a number, see the answer, copy it, move on.

What you get

• 200+ units across 20+ categories — from everyday metres and pounds to specialist units like Hartrees, Saybolt seconds, NATO mils and Becquerels.
• Live results that update as you type, with a clean copy-to-clipboard.
• Favorites — star units you use often and they float to the top.
• Recent conversions stored in your browser, never sent to a server.
• Shareable URLs — every conversion has a unique hash you can bookmark or send.
• Dark mode, full keyboard support, and WCAG AA-friendly contrast.

Privacy by default

We never collect what you type. Your favorites and recent conversions are stored only in your own browser via localStorage. Ads are served by Google AdSense — see our privacy policy for full details.

Got feedback?

We add units and categories based on what people ask for. Drop us a line via the contact page — every message is read.