GB Grid Ref Compass is an iOS app designed by Michael Irving that helps you find your current location on a GB map while in Great Britain. The app provides you with your GB Grid Ref (Ordnance Survey / OS Grid Reference) in addition to a Compass Bearing, Latitude, and Longitude values in both OSGB36 and WGS84 formats. The graphical guide to the "National Grid" system included in the app makes it easy to use.

The app is ideal for use on walks, but it is important to carry a map and physical compass in addition to your iPhone. The app's accuracy depends on the GPS signal of your device, which is indicated on the app. For the best accuracy, use the app in an open space away from trees or hill edges. The app allows you to share your location information in a Text Message (or iMessage), Email, or Tweet.

This app requires Location Services to be enabled on your iPhone, and you must grant permission to the app to use them. The app is compatible with iPhone only, and not with iPod Touch or (non-cellular) iPads due to the lack of GPS and Compass hardware. A sister app is also available for use in Ireland.