When recording geographic coordinates, you will encounter two primary notation systems: Decimal Degrees (DD) and Degrees, Minutes, Seconds (DMS).
While both represent the exact same geographic location on the WGS 84 ellipsoid, they are optimized for vastly different computing environments and human use cases.
Convert Decimal Degrees to DMS Instantly
Input any coordinate in Decimal Degrees, DMS, or UTM to see the live bidirectional conversion with precision rounding.
Overview Comparison Matrix
| Attribute | Decimal Degrees (DD) | Degrees, Minutes, Seconds (DMS) |
|---|---|---|
| Format Example | 37.774929, -122.419416 | 37° 46' 29.7444" N, 122° 25' 9.8976" W |
| Primary Environment | Web mapping (Leaflet, Mapbox, Google Maps), databases (PostGIS), GeoJSON | Maritime nautical charts, aviation flight plans, topographic paper maps |
| Base System | Base-10 decimal standard | Base-60 sexagesimal standard (Babylonian origin) |
| Hemisphere Notation | Positive / Negative signs (+ for N/E, - for S/W) | Cardinal directional letters (N, S, E, W) |
| Database Storage | Native 64-bit floating point (DOUBLE PRECISION, 8 bytes) | Requires string parsing or three separate columns |
| Mathematical Operations | Directly usable in Haversine distance and trigonometry formulas | Must be converted to decimals before trigonometric operations |
The Mathematical Conversion Formulas
Converting DMS to Decimal Degrees (DD)
DD = Degrees + (Minutes / 60) + (Seconds / 3600)
Note: If the hemisphere is South (S) or West (W), multiply the resulting decimal value by -1.
Converting Decimal Degrees (DD) to DMS
1. Whole number = Degrees (e.g. Math.floor(Math.abs(DD))).
2. Multiply fractional remainder by 60 = Minutes.
3. Multiply remaining fractional minute by 60 = Seconds.
Why Web Mapping APIs Standardized on Decimal Degrees
In software engineering, strings are expensive to process, parse, and validate. DMS notation includes multiple non-standard Unicode glyphs (degree symbol °, prime ', double prime ") that create frequent character encoding bugs.
Decimal Degrees allow geospatial engines (such as PostGIS or browser JavaScript engines) to treat coordinates as pure numerical floats. This makes bounding box queries, spatial clustering, and great-circle calculations orders of magnitude faster.