Practical coordinate guide
How to read GPS coordinates
Read latitude first, longitude second. Then identify whether the pair uses decimal degrees, decimal minutes, or degrees-minutes-seconds.
1. Read latitude, then longitude
A standard coordinate pair is written as latitude, longitude. Latitude measures north or south of the equator and ranges from 90° S to 90° N. Longitude measures east or west of the prime meridian and ranges from 180° W to 180° E.
First number: latitude
40.7128
Positive means north of the equator.
Second number: longitude
-74.0060
Negative means west of the prime meridian.
Quick check: a latitude can never exceed 90. If the first number is 120, the pair is probably written longitude-first.
2. Recognize the three coordinate formats
These examples all point to the same location in New York City. Only the notation changes.
40.7128, -74.0060
Commonly used for: Map apps, websites, and data files.
40° 42.768′ N, 74° 0.360′ W
Commonly used for: Marine navigation and some GPS devices.
40° 42′ 46″ N, 74° 0′ 22″ W
Commonly used for: Printed maps, surveying, and traditional notation.
3. Translate signs and compass directions
Decimal coordinates usually use positive and negative signs. DM and DMS usually use the letters N, S, E, and W. They express the same direction rules:
| Direction | Decimal sign | Example |
|---|---|---|
| North | Positive | 40.7128 |
| South | Negative | -33.8688 |
| East | Positive | 151.2093 |
| West | Negative | -74.0060 |
Do not combine a negative sign with S or W. Write either -74.0060 or 74.0060° W, not both.
How to write GPS coordinates correctly
- 1
Put latitude first and longitude second, separated by a comma.
- 2
Use one format consistently; do not mix decimal degrees with DMS.
- 3
Include either signs or compass letters so the hemisphere is clear.
- 4
Keep enough precision: five decimal places in DD is about one meter.
Common mistakes to avoid
Reversing the order
Most tools expect latitude, longitude. Confirm the expected order before pasting into GIS software.
Dropping a minus sign
Changing -74.0060 to 74.0060 moves the point from west of Greenwich to east of it.
Treating minutes as decimals
40° 30′ is 40.5°, not 40.30°, because one degree contains 60 minutes.
Validate before sharing
Open the pair in a map and make sure the pin lands where expected.
Try coordinates in your browser
Find your current latitude and longitude, or convert an existing pair between DD and DMS. Coordinates are processed only on your device.