Tachys — GPS Speedometer

Tachys is a GPS speedometer built for the moments when you want one clear, readable number—on the road, on a train, on a bike, on foot or in the air.

JUST OPEN AND GO
Tachys measures automatically. It combines GPS and motion data, filters unreliable fixes and detects whether you are walking, cycling, driving, traveling by train or flying. Choose km/h, mph or knots.

HONEST WHEN GPS DISAPPEARS
In a tunnel or during a signal outage, Tachys never silently drops to zero or freezes a number. It dims the last known speed and shows how long the signal has been missing.

AT A GLANCE
• Digital LED display and a minimal arc view
• Maximum and average speed, moving time, distance and altitude
• Target speed with a clear reached milestone
• Live Activity for the Lock Screen and Dynamic Island
• Home Screen widget and quick launch from system controls

YOUR TRIPS, YOUR DATA
Tachys records trips locally on your iPhone. Tachys Pro unlocks history with speed charts, route maps and replay, plus GPX and CSV export and shareable trip cards.

ON YOUR WRIST
The Tachys Pro Apple Watch app uses the Watch’s own GPS. Measure away from your iPhone; completed trips transfer back when the devices reconnect.

PRIVATE BY DESIGN
There is no Tachys account, backend, advertising or automatic upload to us. Location and trip history are processed locally unless you choose to export or share them.

The speedometer, current trip data and Live Activity are free. Tachys Pro is a one-time purchase for history, export and the Apple Watch app. No subscription.

Tachys is not a certified navigation or vehicle instrument. Stay aware of your surroundings and follow local laws.