How accurate is a 4-digit grid?

• A. 100 meters
• B. 1000 meters
• C. 10,000 meters
• D. 1 meter

Answer: (B)

A 4-digit grid reference marks a location within a 1-kilometer grid square on the map. The two digits for easting and the two for northing pin you to a specific 1 km by 1 km box, so the accuracy is about 1,000 meters. If you need more precision, you’d use more digits—six-digit grids give about 100-meter accuracy, eight-digit grids about 10 meters. The other options describe significantly finer or coarser precision than a 4-digit grid, so they don’t match what a 4-digit reference can convey.