Coordinate Converter - DD to DMS & UTM
Convert geographic coordinates between Decimal Degrees, Degrees Minutes Seconds, and UTM formats. Supports WGS84 datum for GPS and mapping applications.
Formula
DD = Deg + Min/60 + Sec/3600
To convert DMS to Decimal Degrees: Add degrees, minutes divided by 60, and seconds divided by 3600. Apply negative sign for South or West directions.
Worked Examples
Example 1: DMS to DD: Lower Manhattan
Problem:A survey note gives 40° 42' 46" N, 74° 0' 21" W. Convert both to decimal degrees for a GeoJSON file.
Solution:Latitude: 40 + 46/3600 + 42/60 = 40 + 0.700000 + 0.012778 = 40.712778. Longitude: 74 + 0/60 + 21/3600 = 74.005833, then negate because the direction is West.
Result:40.712778, -74.005833
Example 2: DD to DMS: Sydney Opera House
Problem:Google Maps reports -33.8688, 151.2093. Convert to degrees, minutes and seconds for an aviation chart.
Solution:Latitude: whole degrees 33; 0.8688 x 60 = 52.128, so 52 minutes; 0.128 x 60 = 7.68 seconds; sign is negative so direction is S. Longitude: whole degrees 151; 0.2093 x 60 = 12.558, so 12 minutes; 0.558 x 60 = 33.48 seconds; sign is positive so direction is E.
Result:33° 52' 7.68" S, 151° 12' 33.48" E
Frequently Asked Questions
What is DD vs DMS?
DD (Decimal Degrees) expresses coordinates as single decimal numbers (e.g., 40.7128). DMS (Degrees Minutes Seconds) breaks them down into base-60 units (e.g., 40° 42' 46" N).
Why use Decimal Degrees?
DD is standard for digital mapping, GPS devices, and code because it's easier to calculate distances and plot on charts.
How accurate are GPS coordinates?
5 decimal places (e.g., 40.12345) gives accuracy to about 1.1 meters. 6 decimal places is accurate to ~11cm. 4 decimal places is accurate to ~11 meters (street level).
What do positive and negative numbers mean in DD?
Positive Latitude = North, Negative = South. Positive Longitude = East, Negative = West. Example: -74° Longitude is 74° West.
How to find coordinates on Google Maps?
On desktop, right-click any point and select the numbers at the top of the menu. On mobile, long-press a location to drop a pin and see coordinates in the search bar.
What is latitude and longitude?
Latitude measures distance North/South of the Equator (0° to 90°). Longitude measures distance East/West of the Prime Meridian (0° to 180°).
How many meters is one degree of latitude?
One degree of latitude is approximately 111 kilometers (69 miles). It varies slightly due to the Earth's oblate shape.
Can coordinates locate a specific house?
Yes. With 5-6 decimal places of precision, coordinates can pinpoint a specific front door or even a chair in a room.
Background & Theory
Coordinate Systems:
Latitude (Lat):
- Horizontal lines
- 0° at Equator
- +90° at North Pole, -90° at South Pole
- ~69 miles (111 km) per degree
Longitude (Lng):
- Vertical lines converging at poles
- 0° at Prime Meridian (Greenwich)
- +180° East, -180° West
- Distance per degree varies: ~69 miles at equator, 0 at poles
Conversion Formula:
$$DD = Degrees + \\frac{Minutes}{60} + \\frac{Seconds}{3600}$$
Example:
40° 30' 30"
$$DD = 40 + \\frac{30}{60} + \\frac{30}{3600} = 40 + 0.5 + 0.00833 = 40.50833$$
Datums:
Coordinates depend on the "Datum" (model of Earth's shape). WGS84 is the standard for GPS and Google Maps. Coordinates from older maps (NAD27) may be off by hundreds of meters if not converted.