Latitude/Longitude Format Converter: DD, DMS, DDM

Coordinate format comparison

Decimal places and ground resolution

Each additional decimal place divides the coordinate step by ten. At the equator, one degree of latitude is about 111,320 meters, so the values below describe the approximate north-south spacing represented by a final decimal place. This is coordinate resolution, not measurement accuracy: extra digits do not make a location more certain, and a smartphone GPS reading is often accurate to around 5 meters in typical conditions.

These are approximations for latitude at the equator. Longitude spacing shrinks with latitude by roughly the cosine of the latitude, becoming very small near the poles; the table does not describe GPS error, map alignment, or survey uncertainty. Choose displayed decimals to match the source data and task, and keep the original measurement metadata when accuracy matters.

Reference points

• Greenwich, UK (Prime Meridian): 51.4779° N, 0.0015° W
• Equator / Prime Meridian intersection: 0° N, 0° E (Gulf of Guinea, off West Africa)
• North Pole: 90° N (any longitude)
• South Pole: 90° S (any longitude)

Datum note

Most modern GPS coordinates use the WGS84 datum (World Geodetic System 1984), which is the standard for Google Maps, OpenStreetMap, and GPS devices. Some older US maps and surveys use NAD27 (North American Datum 1927), which can differ from WGS84 by up to ~100 meters depending on location. When precision matters, always confirm which datum a coordinate set uses.

Latitude/Longitude Format Converter

GPS coordinates are expressed in several different formats depending on the application. This tool converts between the three most common formats instantly.

Supported formats

• Decimal Degrees (DD): The simplest format. Latitude and longitude as plain decimal numbers: 40.7128, -74.0060. Negative values indicate South (latitude) or West (longitude).
• Degrees Minutes Seconds (DMS): The traditional surveying format. Each coordinate is split into whole degrees, whole minutes, and decimal seconds with a direction letter: 40°42'46.08"N, 74°0'21.60"W.
• Degrees Decimal Minutes (DDM): Used in many GPS devices and nautical charts. Degrees are whole numbers and minutes are decimal: 40°42.7680'N, 74°0.3600'W.

Accepted input formats

The parser accepts the following common notations. It validates each coordinate before conversion: latitude must be from 90° S to 90° N and longitude from 180° W to 180° E. In DMS and DDM, minutes and seconds must be at least 0 and less than 60; values such as 60 minutes are rejected instead of being silently carried into the next degree. Use N or S for latitude and E or W for longitude.

• 40.7128, -74.0060: comma-separated decimal degrees
• 40°42'46.08"N, 74°0'21.60"W: DMS with symbols and direction letters
• 40°42.768'N, 74°0.36'W: DDM with symbols and direction letters
• 40 42 46 N, 74 0 21.6 W: space-separated DMS without symbols
• 40.7128; -74.0060: semicolon-separated decimal degrees

When converting decimal degrees to a displayed format, the tool rounds DMS seconds to two decimal places and DDM minutes to four. If rounding reaches 60.00 seconds or 60.0000 minutes, it carries that value into the next unit, so the output always remains canonical. A direction letter determines the hemisphere; a contradictory negative sign and direction are reported as an input error rather than being reinterpreted.