Twelve fully offline categories
Twelve fully offline categories — Length, Mass, Temperature, Volume, Speed, Area, Time, Energy, Power, Pressure, Data, Angle. Plus Currency, with live rates from the Frankfurter API and a one-tap refresh.
Rosetta · Unit Converter
Rosetta
Translate measurements instantly.
Convert length, mass, temperature, currency, and more with a fast two-way interface. Core categories work offline, favorites stay on your device, and Rosetta never tracks you.
Coming to the App Store Coming to Google Play
Why Rosetta
Built for quick checks.
Currency that works offline
Currency works offline once you’ve fetched rates at least once. The cache persists; the “as of” timestamp tells you how fresh it is. No signal? You’ll see a quiet line, not a wall of red.
Two-way input, built for speed
Tap a number on either card to make it the active side; the other recomputes instantly. Both sides are first-class — you can convert in either direction with a single tap.
Star your ten favorites
Star any conversion to save it. Up to ten favorites live on the home screen, ordered by how often you use them. Long-press to remove.
Tap to copy, quietly
Tap the inactive number to copy it. A discreet “Copied” toast confirms. No menus, no popovers.
See it work
Fast from either side.
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Home -
Converter -
Unit picker
Privacy, plainly
No accounts, no analytics, no ads, no in-app purchases, no notifications.
Your favorites live on this device only. The single network call Rosetta makes is the public Frankfurter currency rate fetch — everything else stays on your phone. Read the full privacy policy.
Questions
A short list, answered plainly.
- Does it work offline?
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Yes, except live currency rates which require one online fetch (cached afterward).
- Why no settings?
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There is nothing to configure that wouldn’t be a worse default than the one already chosen.
- Is my data tracked?
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No analytics, no accounts, no ads. Nothing leaves the device except the Frankfurter currency rate fetch.