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Convert Lat Long to Decimal Degrees Calculator

Reviewed by Calculator Editorial Team

This guide explains how to convert latitude and longitude coordinates from degrees, minutes, and seconds (DMS) format to decimal degrees (DD) format. Decimal degrees are commonly used in GPS devices, mapping software, and geographic databases.

What is Decimal Degrees?

Decimal degrees is a coordinate format that expresses latitude and longitude as decimal numbers rather than degrees, minutes, and seconds. This format is more precise and easier to work with in calculations and computer systems.

For example, while 40°42'51" North would be written as 40.7142° in decimal degrees.

How to Convert Lat/Long to Decimal Degrees

To convert coordinates from degrees, minutes, and seconds to decimal degrees, follow these steps:

  1. Take the degrees value as the starting point.
  2. Divide the minutes value by 60 and add the result to the degrees.
  3. Divide the seconds value by 3600 and add the result to the previous sum.
  4. For latitude, North is positive and South is negative. For longitude, East is positive and West is negative.

This process converts the coordinate into a single decimal number that represents the same location.

Formula

Decimal Degrees (DD) = Degrees + (Minutes / 60) + (Seconds / 3600)

For latitude:

  • North is positive
  • South is negative

For longitude:

  • East is positive
  • West is negative

Examples

Let's look at a couple of examples to demonstrate the conversion process.

Example 1: Converting 40°42'51" North, 73°59'21" West

Latitude:

  1. Degrees: 40
  2. Minutes: 42 ÷ 60 = 0.7
  3. Seconds: 51 ÷ 3600 ≈ 0.0142
  4. Total: 40 + 0.7 + 0.0142 ≈ 40.7142° North

Longitude:

  1. Degrees: 73
  2. Minutes: 59 ÷ 60 = 0.9833
  3. Seconds: 21 ÷ 3600 ≈ 0.0058
  4. Total: 73 + 0.9833 + 0.0058 ≈ 73.9891° West (negative)

Example 2: Converting 34°3'27" South, 150°55'3" East

Latitude:

  1. Degrees: 34
  2. Minutes: 3 ÷ 60 = 0.05
  3. Seconds: 27 ÷ 3600 ≈ 0.0075
  4. Total: 34 + 0.05 + 0.0075 ≈ 34.0575° South (negative)

Longitude:

  1. Degrees: 150
  2. Minutes: 55 ÷ 60 ≈ 0.9167
  3. Seconds: 3 ÷ 3600 ≈ 0.0008
  4. Total: 150 + 0.9167 + 0.0008 ≈ 150.9175° East

FAQ

Why convert coordinates to decimal degrees?
Decimal degrees are more precise and easier to use in calculations, making them ideal for GPS devices, mapping software, and geographic databases.
How do I know if my coordinates are in the correct format?
Coordinates in decimal degrees will have a decimal point in the number (e.g., 40.7142°). Coordinates in degrees, minutes, and seconds will have degree (°), minute ('), and second (") symbols.
Can I convert decimal degrees back to degrees, minutes, and seconds?
Yes, you can reverse the conversion process by taking the decimal part of the coordinate, multiplying by 60 to get minutes, and then taking the decimal part of the minutes to get seconds.