Coordinates come in several latitude and longitude formats, and that causes real confusion. So this guide explains the three you will meet: DD, DMS and DDM. Then it shows how to read and convert each one.
The same place can be written three ways. First, decimal degrees, or DD. Second, degrees, minutes and seconds, or DMS. Third, degrees and decimal minutes, or DDM. So the number looks different, but the point is identical.
Each format suits a different tool. For example, GPS software likes DD. Paper maps and surveys use DMS. Marine and aviation GPS use DDM. So knowing all three saves a lot of guesswork.
Decimal degrees is one number per axis. For example, 48.8584 and 2.2945. It is easy to store and easy to sort. So most software and web maps use it. Also, a negative sign means south or west.
The whole number is the degrees. The decimal is the fraction of a degree. So more decimals mean more precision. For instance, five decimals place a point within about one metre.
DMS splits each value into three parts. For example, 48°51'30"N. Here 48 is degrees, 51 is minutes, and 30 is seconds. Then a letter gives the hemisphere. So this format is common on maps and deeds.
The formula is short. Take the degrees. Then add the minutes divided by 60. Then add the seconds divided by 3600. Finally, make it negative for south or west. So 48°51'30"N becomes 48.8583.
DDM keeps whole degrees, then writes minutes as a decimal. For example, 48°51.5'N. So it sits between DD and DMS. Marine chartplotters and aviation units use it most.
To reach decimal degrees, divide the decimal minutes by 60. Then add that to the degrees. For instance, 51.5 minutes is 0.858 degrees. So 48°51.5' becomes 48.858.
You do not need the maths by hand. Instead, use the coordinate converter. Just type a value in any of the latitude and longitude formats. Then read DD, DMS, DDM, UTM and Web Mercator at once. It is free and runs in your browser.
Have a sheet of coordinates? Then convert it too. For example, use CSV to KML for Google Earth. The tool reads decimal degrees best, so clean columns help. You can read more at the geographic coordinate system overview.
There are three common ones: decimal degrees (DD), like 48.8584; degrees, minutes and seconds (DMS), like 48°51'30"N; and degrees with decimal minutes (DDM), like 48°51.5'N. They describe the same point in different notations.
Take the degrees, add the minutes divided by 60, then add the seconds divided by 3600. Make the result negative for south or west. For example, 48°51'30"N is 48 + 51/60 + 30/3600 = 48.8583.
Decimal degrees is the safest for software, spreadsheets and web maps. DMS is common on printed maps and surveys, while DDM appears on marine and aviation GPS. Convert to decimal degrees when in doubt.
Latitude runs from -90 to 90 and marks north or south. Longitude runs from -180 to 180 and marks east or west. Any value above 90 must therefore be a longitude.
Yes. A coordinate converter accepts any of the three formats and shows the others instantly, along with UTM and Web Mercator. A browser-based tool does this without uploading anything.
