How To Convert Latitude and Longitude from Degrees, Minutes, and Seconds to Decimal Degrees

Many older reports and databases record latitude and longitude in degrees, minutes, and seconds. These coordinates are now commonly required to be in decimal degree format in order to be used in GIS or other software or online programs. Converting is easy and only takes a few steps. Microsoft Excel or another spreadsheet program makes the process easy for a large number of coordinates.

1. Understand the symbols used to denote degrees, minutes, and seconds. Degrees are marked by a ° symbol. Minutes are marked by a ' symbol. Seconds are marked by a '' symbol.
2. Understand the relationship between degrees, minutes and seconds. One degree is equivalent to 60 minutes. One minute is equivalent to 60 seconds. Therefore, one degree is also equivalent to 3,600 seconds.
3. Do the math. To calculate each coordinate in decimal degrees, use the following calculation:

   Decimal Degrees = degrees + minutes/60 + seconds/3,600

4. Make it easy in Microsoft Excel. Enter the degrees, minutes, and seconds of a coordinate into cell A1:

   If the coordinate has a three digit degree value, enter in the following format: DDDMMSS. (Example. 120° 30' 45" = 1203045) Then enter the following equation into the cell where you want the decimal degree value to appear: =LEFT(A1,3) +MID(A1,4,2)/60+MID(A1,6,2)/3600

   If the coordinate has a two digit degree value, enter in the following format: DDMMSS (Example 75° 15' 20" = 751520). Then enter the following equation into the cell where you want the decimal degree value to appear: =LEFT(A1,2)+MID(A1,3,2)/60+MID(A1,5,2)/3600

   This equation should provide the value of the coordinate in decimal degrees. Be sure to format the destination cell to be a number with at least four decimal places. Double check the result of your equation using the calculation in step 3. Once you are satisfied that you have entered the equation properly, you can copy and paste as often as needed.

5. Remember the " - " sign. If a latitude coordinate is in the southern hemisphere or a longitude coordinate is in the western hemisphere, be sure to put a "-" sign in front of it. This will allow GIS or other spatial software to place it in the right position on earth.