What is the difference between DD, DDM, and DMS?

All three express the same location on Earth using degrees. Decimal Degrees (DD) uses a single floating-point number per axis — e.g. 51.5074° N. Degrees and Decimal Minutes (DDM) splits that into whole degrees plus a decimal fraction of minutes — e.g. 51° 30.444' N. Degrees Minutes Seconds (DMS) goes one step further and gives whole degrees, whole minutes, and a decimal fraction of seconds — e.g. 51° 30' 26.64" N. GPS receivers typically output DDM; mapping software usually stores DD; old paper charts use DMS.

How do I convert decimal degrees to DMS?

Take the absolute value of the decimal degree. The integer part is the degrees. Multiply the decimal remainder by 60 — the integer part of that is the minutes. Multiply the decimal remainder of the minutes by 60 — that gives the seconds. Assign N/S for latitude (positive = N) and E/W for longitude (positive = E). Example: 51.5074° = 51° + (0.5074 × 60)' = 51° 30' + (0.444 × 60)" = 51° 30' 26.64" N.

What is the Haversine formula?

The Haversine formula computes the shortest path between two points on a sphere (great-circle distance). Given latitudes phi_1, phi_2 and longitudes lambda_1, lambda_2 (all in radians): a = sin²((phi_2 - phi_1)/2) + cos(phi_1) · cos(phi_2) · sin²((lambda_2 - lambda_1)/2), then d = 2R · asin(sqrt(a)), where R is the mean Earth radius (6371.0088 km). It is accurate to within 0.3 % for most purposes; Vincenty's formula is more precise for near-antipodal points.

What is bearing and how is it measured?

Bearing is the horizontal direction from one point to another, measured clockwise from true North (0°) to 360°. A bearing of 090° means due East; 180° means due South. The forward bearing is from Point A to Point B; the return bearing is the direction you would travel going back. They are supplementary — roughly 180° apart — but not exactly because the Earth is spherical.

What is UTM and is the converter accurate?

UTM (Universal Transverse Mercator) is a grid coordinate system that divides the Earth into 60 north-south zones, each 6° wide, numbered 1–60 East. Within each zone, positions are given as Easting (metres east of the zone's central meridian, offset by 500,000 m to keep positive) and Northing (metres north of the Equator, with a 10,000,000 m false northing in the Southern Hemisphere). This tool uses the standard series-expansion formula for WGS-84 and is accurate to within 1 metre for latitudes below 80°. It is not suitable for high-precision surveying at extreme latitudes.

What coordinate formats does the converter accept?

The parser accepts: plain decimal degrees (51.5074 or -0.1278), decimal degrees with direction suffix (51.5074N or 0.1278W), DMS with degree/minute/second symbols (51° 30' 26.6" N), DDM (51° 30.444' N), colon-separated DMS (51:30:26.6N), and radians with an 'r' or 'rad' suffix (0.8988rad). Positive values default to N/E; negative to S/W.

Latitude & Longitude Converter

A latitude and longitude converter that handles every common GPS and mapping coordinate format — decimal degrees (DD), degrees and decimal minutes (DDM), degrees-minutes-seconds (DMS), radians, and approximate UTM grid references. Paste any coordinate string, pick your output format, and copy the result in one click. The built-in Distance & Bearing tab computes the great-circle (Haversine) distance between two points in kilometres, miles, and nautical miles, along with the forward and return compass bearing.

Everything runs in your browser — no data is ever uploaded or stored.

How the format conversions work

A geographic coordinate is simply an angle measured from a reference line: latitude from the Equator (positive = North), longitude from the Prime Meridian (positive = East). The same angle can be written in several equivalent ways.

Decimal Degrees (DD) — the simplest form, used by most APIs and databases:

lat = 51.507400°, lon = -0.127800°

Degrees Decimal Minutes (DDM) — common on GPS receivers and nautical charts. The fractional degree is converted to minutes (multiply by 60):

lat = 51° 30.444’ N, lon = 0° 7.668’ W

Degrees Minutes Seconds (DMS) — traditional cartographic format. The fractional minute is further converted to seconds (multiply by 60):

lat = 51° 30’ 26.64” N, lon = 0° 7’ 40.08” W

Radians — used in mathematical calculations (including Haversine):

lat = 0.89885 rad, lon = -0.00223 rad

UTM (approximate) — a metric grid system. The Earth is divided into 60 zones of 6° longitude; within each zone the position is given as Easting (m) and Northing (m). Useful when working with maps that use a Cartesian grid rather than angular coordinates.

Great-circle distance — the Haversine formula

The shortest path between two points on a sphere is a great-circle arc. The Haversine formula computes this distance without floating-point overflow for opposite sides of the globe:

a = sin²(Δφ/2) + cos φ₁ · cos φ₂ · sin²(Δλ/2)

d = 2R · asin(√a)

where φ is latitude in radians, λ is longitude in radians, and R is the mean Earth radius (6 371.0088 km per IUGG). The tool also reports the initial bearing — the clockwise angle from true North at which you leave Point A to reach Point B — and the return bearing from B back to A.

Worked example

London Heathrow (LHR) to Paris Charles de Gaulle (CDG):

Field	Value
LHR lat / lon	51.477500° N, 0.461389° W
CDG lat / lon	49.009722° N, 2.547778° E
DD to DMS (LHR lat)	51° 28’ 39.0” N
DD to DMS (CDG lat)	49° 0’ 35.0” N
Great-circle distance	≈ 341 km / 212 mi / 184 NM
Forward bearing (LHR → CDG)	≈ 118° (ESE)
Return bearing (CDG → LHR)	≈ 299° (WNW)
UTM zone (LHR)	30U — Easting ≈ 531 074 m

The Haversine intermediate value a = 0.00718, giving c = 0.05352 rad and d = 2 × 6 371 × asin(0.08473) ≈ 341.0 km.

Formula note

The Haversine formula assumes a spherical Earth and has an error of up to 0.3 % for antipodal points. For geodetic surveying requiring sub-metre accuracy, use the Vincenty inverse formula on the WGS-84 ellipsoid (a = 6 378 137 m, f = 1/298.257 223 563). The UTM conversion here uses the standard power-series expansion for WGS-84 and is accurate to within 1 m for latitudes below ±80°.