Coordinate Master

39 reviews
Content rating
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About this app

This powerful geodesy app allows you to convert coordinates between many of the world's coordinate systems, compute geoid offsets, and estimate the current or historic magnetic field for any location. It also includes a calculator tool as well as surveying tools to compute the point scale factor, grid convergence, traverse, inverse, and sun angle. You can also store multiple points and compute boundary length and area on them, or import/export them to CSV files.

The app uses the PROJ4 library and a lookup file containing projection and datum parameters to support over 1700 coordinate systems. Lat/lon, UTM, US coordinate systems (including US State Plane), Australian coordinate systems (including GDA2020), UK coordinate systems (including Ordinance Survey) and many, many others are supported. You can also create your own coordinate systems if you know the parameters.The app also supports affine transformations to allow you to set up local grid systems. See for details.

The app either takes manual coordinate input or uses your current GPS location. The computed location can be displayed in Google Maps via your web browser with a single button press. It also supports MGRS grid references.

You can export any lat/lon, UTM or transverse Mercator coordinate systems to a HandyGPS datum (.hgd) file for use as a custom datum in HandyGPS.

The magnetic field calculator page computes the Earth's current or historical magnetic field at a given location. The magnetic declination computed is useful for compass navigation since it represents the difference between true north and magnetic north. Field inclination and total intensity are also computed. This tool uses the International Geomagnetic Reference Field model (IGRF-13). See for full details. Years from 1900 through to 2025 are supported.

The app can also compute the geoid height offset for a given location, using the EGM96 model. Geoid offset can be subtracted from the height reported by GPS to give your actual height above sea level.

The app also includes a sun angle calculator which can be used to compute the location of the sun in the sky at any location for any date and time.

Online help for the app is available at

A version of this app which allows batch coordinate conversions is now available for Windows. See

Permissions required: (1) GPS - to determine your location, (2) SD card access - to read and write user projections file.
Updated on
Jun 7, 2022

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
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No data collected
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39 reviews
Matt Cunningham
April 27, 2021
Fantastic. If you need to perform conversions between different coordinate systems accurately & faithfully, this app is simply the best. The list of supported systems is immense, and the calculations are reliable - unlike some converters using simplified translations, resulting in degraded accuracy. This app is quite niche, which might explain why it hasn't received the wider acclaim it deserves. EDIT: I wished for a very minor, quite niche feature. Within days, the dev added it. Awesome! 👌
2 people found this review helpful
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April 23, 2021
Not sure if this is what you mean by sheet codes, but if you have the British National Grid selected and press the third button above the co-ordinate system name, the app will show you the OS grid ref.
A Google user
October 24, 2018
This is the only android app I've ever found that can compute UTM grid convergence (for setting your compass to grid declination, for paper-map navigation). The UX isn't perfect, but IMHO it definitely deserves all 5 stars for having that one critical feature.
4 people found this review helpful
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June 26, 2020
Amir Siahy
May 11, 2021
It's a great app. The only defect which made me to give it 4 stars, is the old gingerbread era GUI design. If it's not make too trouble, dear developers please concern the material design guidelines in new user interface.
2 people found this review helpful
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What's new

7.8: Fixed a bug related to coordinate systems with a spherical ellipsoid.
7.7: Allow Coordinate Master to handle "geo" intents via the Android share menu.
7.6: Bug fix.
7.5: Handle special arabic number characters.
7.4: Added option to show heights in metres or feet.
7.3: Show location of data files on "About" dialog.
7.2: Allow entry of OS grid refs when British National Grid selected.
7.1: Upgraded to target Android SDK 30 as required by Google.