How to use it
- Choose DMS → decimal degrees, or the reverse.
- Enter degrees, minutes and seconds, or paste a coordinate like 40°42′46″ N.
- Set the direction: N/E positive, S/W negative.
- Copy the decimal degrees for your map app.
The formulas
Decimal degrees = degrees + minutes ÷ 60 + seconds ÷ 3600
Example: 40° 42′ 46.08″ N = 40 + 42/60 + 46.08/3600 = 40.7128°.
Going the other way:
- The whole number is the degrees: 40.7128 → 40°.
- Multiply the decimal part by 60: 0.7128 × 60 = 42.768 → 42′.
- Multiply the remaining decimal by 60: 0.768 × 60 = 46.08″.
So 40.7128° = 40° 42′ 46.08″.
Minutes and seconds here are units of angle, not time, but they work the same way: 60 seconds make a minute and 60 minutes make a degree. Keep the seconds to one or two decimals; more than that is beyond the accuracy of most GPS receivers. When you convert a negative decimal (a south latitude or west longitude), convert the absolute value and put the sign or the S or W letter back at the end.
North, south, east and west
In decimal degrees, direction is shown by the sign:
- North latitude and east longitude are positive.
- South latitude and west longitude are negative.
All of the contiguous United States lies in the western hemisphere, so US longitudes are negative in decimal form. New York City is roughly 40.7128, −74.0060, which in DMS is 40° 42′ 46″ N, 74° 0′ 22″ W. When you paste a value with a letter (N, S, E or W) the tool sets the sign for you.
Three ways to write a coordinate
| Format | Example |
|---|---|
| Decimal degrees (DD) | 40.7128 |
| Degrees and decimal minutes (DDM) | 40° 42.768′ |
| Degrees, minutes, seconds (DMS) | 40° 42′ 46.08″ |
Map apps and most websites use decimal degrees. Paper maps, nautical charts and many GPS units use DMS or DDM. Geocaching listings typically use degrees and decimal minutes. The tool shows all three, plus the angle in radians for math and programming.
How precise is a coordinate?
One degree of latitude is about 111 km (69 miles). One minute is about 1.85 km (1.15 miles), which is one nautical mile, and one second is about 31 m (101 ft). So:
| Decimal places | Precision |
|---|---|
| 2 | about 1.1 km |
| 4 | about 11 m |
| 5 | about 1.1 m |
| 6 | about 11 cm |
Longitude distances shrink toward the poles, so these figures are for latitude. Six decimal places is more than any phone GPS can actually measure.
Pasting and copying
You can paste a coordinate in one piece, with or without symbols: 40°42′46″ N, 40 42 46 N and −74 00 21 all work. Minutes and seconds must be less than 60. The copy button copies decimal degrees with a period as the decimal separator, which is what Google Maps, Apple Maps and GIS software expect. Enter latitude and longitude one at a time. Everything is calculated in your browser, so your locations aren't sent anywhere.
Frequently asked questions
How do I convert DMS to decimal degrees?
Add degrees + minutes/60 + seconds/3600, and make it negative for south or west.
Why is my longitude negative?
Longitudes west of the Prime Meridian, including all of the contiguous US, are negative in decimal degrees.
How far is one second of latitude?
About 31 meters, or roughly 101 feet.
Which format does Google Maps use?
Decimal degrees, latitude first: for example 40.7128, -74.0060. It also accepts DMS if you type it with symbols.
What are radians?
Another unit for angles used in math and programming: 180° equals π radians, so 1° ≈ 0.01745 rad.
Last updated: November 12, 2026