CADGISHow to use the converter
- Choose the direction: DMS → Decimal or Decimal → DMS.
- Select Latitude or Longitude.
- Enter your value. For DMS, pick the direction N/S or E/W. For decimal degrees, use a minus sign or a letter (for example
-33.8688or33.8688 S). - Set how many decimal places you want, then copy the result.
What is DMS (degrees, minutes, seconds)?
DMS writes an angle in sexagesimal form: one degree is divided into 60 minutes (′), and one minute into 60 seconds (″). It is the traditional format on topographic maps, survey plans, GPS receivers and legal land descriptions, for example 33° 52' 07.68" S.
What are decimal degrees (DD)?
Decimal degrees express the same angle as a single number, such as -33.868800. It is the standard format for GIS software (QGIS, ArcGIS), web maps, GPS data exchange and databases. Instead of a letter, the sign shows the hemisphere:
- Latitude: North is positive, South is negative (range -90 to 90).
- Longitude: East is positive, West is negative (range -180 to 180).
Conversion formulas
DMS to decimal degrees
DD = Degrees + Minutes / 60 + Seconds / 3600
Then make the result negative for South latitudes or West longitudes.
Decimal degrees to DMS
Degrees = whole part of |DD|
Minutes = whole part of (fraction × 60)
Seconds = remaining fraction × 60
This tool rounds only the displayed seconds. If rounding would give 60 seconds, it carries into the minutes, so you never see results like 12' 60.00".
Worked examples
| Location | DMS | Decimal degrees |
|---|---|---|
| Sydney latitude | 33° 52' 07.68" S | -33.868800 |
| Sydney longitude | 151° 12' 33.48" E | 151.209300 |
| London latitude | 51° 30' 26.64" N | 51.507400 |
| London longitude | 0° 07' 40.08" W | -0.127800 |
Example: 40° 26' 46" N to decimal
40 + 26/60 + 46/3600 = 40 + 0.433333 + 0.012778 = 40.446111
Example: -79.982222 to DMS
Degrees = 79. 0.982222 × 60 = 58.93332, so minutes = 58. 0.93332 × 60 = 56.0 seconds. The value is negative longitude, so the result is 79° 58' 56.00" W.
How many decimal places do I need?
| Decimal degrees | DMS seconds | Approx. precision on the ground |
|---|---|---|
| 4 places (0.0001°) | 0 places (1") | ≈ 11 m / ≈ 31 m |
| 5 places (0.00001°) | 1 place (0.1") | ≈ 1.1 m / ≈ 3.1 m |
| 6 places (0.000001°) | 2 places (0.01") | ≈ 0.11 m / ≈ 0.31 m |
| 8 places (0.00000001°) | 4 places (0.0001") | ≈ 1 mm / ≈ 3 mm |
Distances are for latitude (north–south). East–west distances for longitude get smaller toward the poles.
Frequently asked questions
Why is my decimal coordinate negative?
Negative values are South latitudes or West longitudes. For example, anywhere in the Americas has a negative longitude.
Can I enter seconds with decimals?
Yes. Seconds can include decimals, such as 07.683. They must be less than 60.
Does this tool change datums or coordinate systems?
No. It only changes the number format. The datum (for example WGS84) stays the same.