This calculator converts between decimal degrees and degrees, minutes and seconds (DMS), the two main ways latitude and longitude are written for GPS devices, surveying, marine charts and aviation. Toggle between Decimal to DMS or DMS to Decimal, enter either a decimal degree value (for example -36.8485) or separate degrees, minutes and seconds figures, then choose whether the coordinate is positive (north or east) or negative (south or west). Four NZ reference points, the latitudes of Auckland, Wellington, Christchurch and Queenstown, are built in so you can load a real example instantly. It returns the decimal degrees, the DMS equivalent, and the degrees decimal minutes (DM) format used on marine and outdoor GPS units, alongside a step by step breakdown of how the degrees, minutes and seconds are derived, plus a reverse check that adds them back together to confirm the total matches your original value. Use it whenever you need to move a coordinate between systems, such as reading a DMS value off a survey plan or nautical chart before entering it into Google Maps. The conversion is exact base 60 arithmetic, so there is no rounding error beyond the decimal places you keep, though the tool does not perform coordinate datum transformations, so check your source data uses the same datum, such as NZGD2000 or WGS84, before relying on the result.
Loading a preset switches to Decimal → DMS mode and fills the decimal degrees field with that location's latitude, so you can see the DMS equivalent used on marine charts and survey plans.
A degree of angle or latitude/longitude can be split into smaller units the same way an hour is split into minutes and seconds. One degree equals 60 arcminutes, and one arcminute equals 60 arcseconds, so one degree equals 3,600 arcseconds. This base 60 (sexagesimal) system dates back to Babylonian astronomy and is still the standard for expressing latitude and longitude on marine charts, survey plans, and aviation documents.
To convert a decimal degree value to degrees, minutes and seconds, follow three steps:
For example, 41.1234 degrees: 41 is the degrees. The fraction 0.1234 times 60 equals 7.404, so 7 is the minutes. The fraction 0.404 times 60 equals 24.24, giving 24.24 seconds. The result is written as 41 degrees 7 minutes 24.24 seconds, or 41 deg 7 min 24.24 sec.
To reverse the process, divide the minutes by 60 and the seconds by 3,600, then add both to the degrees:
| Formula | Description |
|---|---|
| Decimal degrees = D + M/60 + S/3600 | D is degrees, M is minutes, S is seconds |
Using the same example: 41 + 7/60 (0.1167) + 24.24/3600 (0.00673) equals 41.1234 decimal degrees, matching the original value.
Latitude and longitude use a hemisphere letter (N, S, E, W) alongside DMS, but decimal degree values use a positive or negative sign instead. Northern latitudes and eastern longitudes are positive. Southern latitudes and western longitudes are negative. Auckland's latitude, for example, is written as either 36 degrees 50 minutes 54.6 seconds S or as -36.8485 in decimal form. Always convert the unsigned DMS value first, then apply the sign or hemisphere letter afterward.
All three formats describe the exact same angle or location. Converting between them is purely arithmetic and introduces no loss of accuracy provided enough decimal places are used.
Sources: Standard sexagesimal (base 60) degree, minute, second conversion used in geodesy, surveying and navigation (International Hydrographic Organization chart conventions; Land Information New Zealand survey standards, linz.govt.nz).
This calculator performs a standard mathematical conversion between decimal degrees and degrees, minutes, seconds notation. It does not perform coordinate datum transformations (for example between NZGD2000 and WGS84). Always round to an appropriate number of decimal places for your application.