Know exactly where you are.
In any format.
Professional GPS precision with consumer app simplicity. Six coordinate formats. Geodesic calculations. Routes and tracks. Works offline.
Get the App
Capture waypoints, navigate with precision, and work offline anywhere GPS satellites can reach.
Download on App Store Download on Play StoreiPhone • iPad • Apple Watch • Android
Try It Now
See your current location in all six formats, powered by GeographicLib.
Your location is sent to our server for conversion only.
We do not store or log coordinates.
Every Format That Matters
Coordinates in the formats professionals actually use.
Built for Real Navigation
Geodesic Precision
Powered by GeographicLib. The same calculations used by governments and militaries. Not flat-earth approximations.
Capture Instantly
One tap saves your current location with full accuracy data. Name it later, or let reverse geocoding do it for you.
Navigate Back
Large compass with bearing and distance. Works in the backcountry, at sea, or anywhere GPS satellites can reach.
Routes & Tracks
Chain waypoints into routes. Record your path as a track. Export and import GPX files.
Works Offline
No cell service needed. All calculations happen on-device. Your data stays on your device.
Night Vision
Red-on-black mode preserves dark adaptation. Automatic activation based on local sunrise and sunset.
Apple Watch
Capture waypoints from your wrist. Voice naming. Quick coordinate checks without pulling out your phone.
CloudKit Sync
Optional sync across your devices. Your waypoints everywhere you need them.
For People Who Need Their Location
Outdoor Enthusiasts
Save your trailhead. Record your hike. Find your way back. Gemma GPS works in places where cell service doesn't.
Professionals
MGRS, UTM, mils. GeographicLib geodesic calculations. The coordinate precision you need, without the complexity you don't.
Ham Radio Operators
Your grid square at a glance. Maidenhead locators from field to extended precision for contests and DX.
Travelers
Tag your hotel. Tag the subway. Never waste twenty minutes wondering which way to walk in a new city.
Specialized Tools
Beyond basic navigation, Gemma GPS includes professional tools for specific use cases.
Tactical
- Call for Fire calculator
- 9-Line CAS format
- Lasing calculator
Emergency
- Marine Mayday format
- Aviation emergency format
- SAR coordinate sharing
Surveying
- Area calculator
- Slope calculator
- Distance measurement
Questions & Answers
What makes Gemma GPS different from other GPS apps?
Gemma GPS is built for people who work with actual coordinates, not just addresses. It displays six coordinate formats (Decimal, MGRS, DDM, DMS, UTM, Maidenhead), uses geodesic calculations on the WGS84 ellipsoid via GeographicLib, and works completely offline. It's the precision of a professional GPS device in a consumer app.
How accurate are the calculations?
Distance and bearing use GeographicLib's geodesic algorithms on the WGS84 ellipsoid—the same calculations used by governments and militaries worldwide. This isn't flat-earth math or great-circle approximations. Coordinate conversions (UTM, MGRS, Maidenhead) are precise to the limits of the formats themselves.
Does it work without cell service?
Yes. All calculations happen on-device. The only features that require connectivity are optional: reverse geocoding (to name locations by address) and CloudKit sync. GPS works anywhere you can see satellites.
Can I import my existing waypoints?
Gemma GPS imports and exports standard GPX files. You can share waypoints via the URL scheme (gemmagps://coordinates/?lat=X&lon=Y&name=Name) and extract GPS coordinates from photo EXIF data.
What about battery life?
Gemma GPS only uses GPS when the app is open and you're actively checking location. It never tracks in the background. For extended backcountry use, enable Airplane Mode when you don't need cellular—but note this disables GPS too, so request your position first.
Is my location data private?
Your waypoints are stored locally and in your iCloud account (if you enable sync). Location data is only sent to Apple for optional reverse geocoding. We don't have servers. We don't collect your data. The database file is encrypted when your device is locked.
What does the Apple Watch app do?
Quick capture: tap to save your current location and optionally name it with voice. View your coordinates in multiple formats. Check bearing and distance to an active waypoint. It's for glances and fast captures, not full waypoint management.
What are the tactical and emergency tools?
Specialized formatters for military and emergency communications: Call for Fire reports, 9-Line CAS briefs, Marine Mayday position reports, and aviation emergency formats. These tools format your current position in standardized ways for radio communications.
Does it support VoiceOver?
Yes. Full VoiceOver accessibility throughout the app. Dynamic Type support for adjustable text sizes. The app was designed with accessibility in mind from the start.
Precision coordinates for people who need them.
No subscription. No account required. Your data stays yours.