Latitude and Longitude Converter

Geographic coordinates can be written in different formats.

Decimal Degrees (DD):

• Example: 40.7128, -74.0060 (New York City)
• Positive = North/East, Negative = South/West

Degrees Minutes Seconds (DMS):

• Example: 40 deg 42’ 46.08" N, 74 deg 0’ 21.6" W

Converting DD to DMS:

1. The whole number is the degrees: 40
2. Multiply the decimal by 60 for minutes: 0.7128 x 60 = 42.768
3. The whole number is minutes: 42
4. Multiply the remaining decimal by 60 for seconds: 0.768 x 60 = 46.08

Converting DMS to DD:

• DD = Degrees + (Minutes / 60) + (Seconds / 3600)
• 40 + (42/60) + (46.08/3600) = 40.7128

Notable coordinates:

• New York: 40.7128 N, 74.0060 W
• London: 51.5074 N, 0.1278 W
• Tokyo: 35.6762 N, 139.6503 E
• Sydney: 33.8688 S, 151.2093 E

Which format you need depends on where the number is going. Software, mapping APIs, and GPS apps almost always want decimal degrees, because a single signed number per axis is easy to store and do math on. Paper charts, surveying, and aviation still lean on degrees-minutes-seconds, the older notation that predates calculators. The common mistake when converting is the sign: decimal degrees uses negatives for south and west, while DMS uses the letters N/S/E/W, so dropping a minus sign quietly flips you to the wrong hemisphere.

That is why the hemisphere here is a separate selector rather than a minus sign on the degrees box. In DMS the degrees, minutes and seconds are all plain magnitudes and the letter carries the direction, so there is nowhere for a negative to live. Trying to force one in breaks worst exactly where you would least notice: London sits at 0.1278 degrees west, and a degrees field holding “minus zero” is indistinguishable from one holding zero, so the west vanishes. Everywhere within one degree of the prime meridian or the equator has the same problem.

Do not use both conventions at once, either. A coordinate written as -74.0060 W has said “west” twice, and whichever piece of software reads it next has to guess which one you meant.

Decimal places matter too, because precision costs digits. At the equator, the fifth decimal of a degree is about one meter, the fourth is about ten meters, and the sixth gets you to roughly ten centimeters. So 40.71280 pins a spot to within a meter, while 40.71 only narrows it to about a kilometer. Copy enough decimals for the job and no more: a street address needs five, a country-level marker needs two.