GPS devices, marine equipment, and traditional navigation each favor a different coordinate format, this converter handles all three, letting you enter coordinates in whichever format you have and read the others instantly.
How to use this coordinates converter
- Choose your input format tab: Decimal Degrees, DMS, or DDM.
- Enter your Latitude and Longitude in that format.
- Read the converted value in Decimal Degrees, plus the full breakdown across all three formats.
The three coordinate formats explained
Decimal Degrees (DD), for example 40.7484, is the format used by GPS devices and mapping software, a single decimal number per axis. Degrees Minutes Seconds (DMS), for example 40° 44′ 54.2″ N, is the traditional navigational format, dividing each degree into 60 minutes and each minute into 60 seconds. Degrees Decimal Minutes (DDM), for example 40° 44.903′ N, is common on marine GPS units, a hybrid that keeps whole degrees but expresses minutes as a decimal rather than splitting further into seconds.
DMS to DD: Decimal Degrees = Degrees + (Minutes ÷ 60) + (Seconds ÷ 3600)
DDM to DD: Decimal Degrees = Degrees + (Decimal Minutes ÷ 60)
Why different fields prefer different formats
Decimal degrees are the easiest format for software and mapping APIs to work with directly. DMS remains the traditional standard in classical navigation and is still commonly printed on maps and in older records. DDM strikes a middle ground favored by many marine GPS units, offering more precision than whole-degree DMS without requiring a full seconds breakdown.
The sign convention this converter follows
Following WGS84 convention, positive latitude represents North and positive longitude represents East, with negative values representing South and West respectively, matching how most GPS and mapping systems represent coordinates internally.
Frequently asked questions
What’s the difference between DMS and DDM formats?
DMS (Degrees Minutes Seconds) splits each degree fully into minutes and seconds, while DDM (Degrees Decimal Minutes) keeps whole degrees but expresses the minutes portion as a decimal instead of splitting further into seconds. DDM is common on marine GPS units.
Why do positive latitude and longitude mean North and East?
This follows the WGS84 convention used by GPS systems worldwide, positive latitude is North of the equator, positive longitude is East of the prime meridian, with negative values representing South and West.
