What is a Datum in Simple Terms?
If you put the same GPS coordinates into two different maps, you might end up in two different places. The culprit? The Datum.
Need to convert or check coordinates right now?
Skip the guide and instantly format, convert, or locate your coordinates on the map using our free tool.
Need to convert coordinates instantly? Use our free tool below.
Convert Coordinates in Seconds (No Setup Needed)The Simple Explanation
The Earth isn't a perfect sphere; it's lumpy. A "Datum" is essentially a mathematical model of that lumpiness. Because different countries model the Earth differently, they use different datums.
Real World Example
WGS84 is the global datum used by GPS. NAD83 is the datum used for North America. If you mix them up, your coordinates will be off by about 1 to 2 meters.
Pro Tip
When entering coordinates into map apps, always double-check if there is a negative sign (-). Missing a negative sign on longitude will place you on the opposite side of the planet!
Frequently Asked Questions
Does a Datum shift matter for driving?
For driving, no. But for property lines, surveying, and aviation, a 2-meter datum shift can cause massive legal issues.
People also try:
Warning: Verify Your Calculation
Coordinate accuracy varies by device and datum. Do not use these results for legal or construction purposes without checking:
GPS Accuracy Alert
Your phone's GPS can be off by 30 meters. This can cause critical errors in your data.
Check My Accuracy →Datum Shift Risk
Using the wrong coordinate system (e.g. WGS84 vs NAD83) creates a permanent 1-meter offset.
Verify My Datum →