GPS coordinate formats explained: decimal degrees vs DMS

If you have ever copied a location from Google Maps, a survey report, and an aviation chart, you may have noticed the same spot written three completely different ways. One says 6.200000, another says 6°12'00"S, and a third mixes the two. None of them is wrong — they are just different notations for the same point on Earth. This guide explains what each format means, when you will meet it, and how to move between them safely.

Latitude and longitude: the basics

Every coordinate is a pair of numbers. Latitude measures how far north or south you are from the equator, from 0° at the equator to 90° at each pole. Longitude measures how far east or west you are from the Prime Meridian in Greenwich, from 0° to 180°. Indonesia sits mostly south of the equator and east of Greenwich, so most Indonesian coordinates have a south latitude and an east longitude.

Decimal degrees (DD)

Decimal degrees write the whole coordinate as two plain numbers, for example -6.200000, 106.816666. This is the format almost every digital map and API uses, because it is just two floating-point values that are trivial to store, compare and feed into calculations. The sign carries the direction: a negative latitude means south, a negative longitude means west.

Precision depends on the number of decimal places. Five decimals locate you to about a metre, which is enough for almost any everyday need; six decimals reach roughly ten centimetres. Adding more digits beyond what your source actually measured does not add real accuracy — it only looks precise.

Degrees, minutes, seconds (DMS)

DMS splits each degree into 60 minutes, and each minute into 60 seconds — the same system used for time. The coordinate above becomes 6°12'00"S, 106°48'59.99"E. You will see DMS on nautical and aviation charts, in surveying, and in older official documents, because it was the standard long before computers. It reads naturally to a human but is awkward for software, which is why conversion comes up so often.

Converting DMS to decimal by hand

The formula is simple: decimal = degrees + minutes/60 + seconds/3600, then make it negative if the direction is South or West. For 6°12'00"S that is 6 + 12/60 + 0/3600 = 6.2, and because it is South, the answer is -6.2. Going the other way, you take the whole-number part as degrees, multiply the remainder by 60 for minutes, and repeat for seconds.

Which format should you use?

• Use decimal degrees for anything digital — links, spreadsheets, databases, code and APIs all expect it.
• Keep DMS when a chart, permit or legal document is written that way, so it matches the official record.
• Always note the hemisphere (N/S, E/W) or the sign — a missing minus sign can put you on the wrong continent.

When you do need to switch formats, do it with a converter rather than rounding by hand, since manual rounding is where precision quietly leaks away. Our decimal-to-DMS and DMS-to-decimal tools run entirely in your browser, and the distance calculator can then measure the straight-line gap between two points once they are in the same format.