About

Geographic Information Systems (GIS) and standard navigation APIs (like Google Maps) typically require coordinates in Decimal Degrees (DD). However, legacy survey data and maritime charts often list positions in Degrees, Minutes, and Seconds (DMS). Converting between these formats requires strict handling of the base-60 (sexagesimal) system used for minutes and seconds. This tool processes the three distinct components to generate a precise decimal float, automatically applying negative signs for South and West hemispheres.

Formulas

The conversion sums the fractional parts of degrees. Since there are 60 minutes in a degree and 3600 seconds in a degree:

DD = (D + M60 + S3600) × Sign

Where Sign is -1 if direction is South or West, and 1 otherwise.

Reference Data

Format	Example	Usage
DMS	40° 26" 46" N	Navigation charts, Legal boundaries
DMM	40° 26.767" N	GPS Handhelds, Geocaching
DD	40.446111	Google Maps, Database storage

Frequently Asked Questions

In the Decimal Degree system, the Equator is 0. Coordinates South of the Equator are negative latitude. The Prime Meridian (Greenwich) is 0. Coordinates West of Greenwich (like the Americas) are negative longitude.

Both must be less than 60. If you have 61 seconds, that is actually 1 minute and 1 second. This tool validates inputs to prevent syntax errors.

Standard DMS precision (to integer seconds) offers accuracy to roughly ~30 meters. Decimal degrees with 6 decimal places (e.g., 40.123456) offer accuracy to ~11 centimeters.

Yes. The process involves taking the integer part as Degrees, multiplying the decimal remainder by 60 to get Minutes, and repeating for Seconds.