Legal
Privacy
Last updated 19 September 2026
Fathom is a unit converter. You can convert metric, imperial, US customary, and other units without creating an account or giving a name, email, or password.
What stays on your device
Recent conversions may be stored in your browser (localStorage) so the last pairs you used are easy to resume. That list never leaves your device. Clearing site data in the browser deletes it.
Visit count
The home page shows a small visit counter. It stores a single number — how many times the home page has been loaded — with no visitor identifier, profile, or advertising ID attached.
Advertising
Google AdSense may serve advertisements and may use cookies or similar identifiers to personalise or measure ads, according to Google’s privacy policy. You can manage ad personalisation in your Google account or browser settings.
Share buttons
Footer share links open X, Facebook, LinkedIn, Reddit, WhatsApp, Telegram, Pinterest, or your mail app. Those services receive the page address you choose to share, under their own policies. Fathom does not run a social login.
Amazon Associates
The shop page contains Amazon affiliate links: Amazon.co.uk (tag stewartferris-21) and Amazon.com (tag upcottstudios-20). As an Amazon Associate, Fathom earns from qualifying purchases. If you follow a link and buy, Amazon may set its own cookies under Amazon’s privacy notice. We do not receive your Amazon account details.
What we do not do
We do not sell personal information. We do not require an account. Conversion values you type are used to compute a result in your session and are not stored as a personal history on our servers.
Contact
Questions about this policy: [email protected]