Who Uses DD
Web developers embed DD coordinates in URLs and databases because the format requires no parsing. Google Maps, OpenStreetMap, and virtually every mapping API accept DD. It is the default output format for most GPS receivers in their menu settings.
- Web developers & APIs
- Google Maps / mapping apps
- GIS databases (PostGIS, etc.)
- General navigation
How to Read DD Coordinates
- Latitude is the first number: positive = North, negative = South.
- Longitude is the second number: positive = East, negative = West.
- The decimal portion represents fractions of a degree (not minutes or seconds).
- 5 decimal places gives ~1 meter precision; 6 gives ~10 cm.
Converting DD by Hand
DD is the base format — all other conversions start here. To convert FROM DMS to DD: DD = Degrees + (Minutes/60) + (Seconds/3600). Apply negative for S or W.
Frequently Asked Questions
How many decimal places do I need?
4 places = ~11 m accuracy, 5 places = ~1 m, 6 places = ~0.1 m. For most mapping work, 5–6 decimal places is sufficient.
Is longitude or latitude first?
In the DD convention, latitude comes first. However, GeoJSON (used in most APIs) reverses this to [longitude, latitude]. Always check your API documentation.
What is the range of valid coordinates?
Latitude: –90 to +90. Longitude: –180 to +180.
How do I enter DD in Google Maps?
In the Google Maps search box, type the latitude, then a comma, then the longitude. Example: 48.8584, 2.2945