Nautical Distance Calculator
Calculate the great-circle distance between two GPS positions in nautical miles, kilometres and statute miles.
Enter coordinates in Degrees and Decimal Minutes: DD° MM.mmm′ N/S | DDD° MM.mmm′ E/W
Departure Position
51° 30.444’ N, 000° 7.668’ W
Destination Position
48° 51.396’ N, 002° 21.132’ E
Results are planning estimates. Verify navigation, weather, vessel and operational information using appropriate professional sources.
What Is the Nautical Distance Calculator?
This calculator uses the Haversine formula to compute the great-circle distance between two positions on the Earth's surface. Coordinates are entered in Degrees and Decimal Minutes (DD° MM.mmm′) format — the standard format used in maritime navigation, ECDIS systems and chart plotters. Results are given in nautical miles, kilometres and statute miles.
How to Use the Nautical Distance Calculator
- Enter the departure position in DD° MM.mmm′ N/S and DDD° MM.mmm′ E/W format.
- Enter the destination position in the same format.
- Click Calculate to see the great-circle distance.
Formula
Worked Example
London: 51° 30.444′ N, 000° 07.668′ W
Paris: 48° 51.396′ N, 002° 21.132′ E
Distance ≈ 183 nmi = 339 km = 211 miles
Understanding Your Result
The great-circle distance is the shortest distance between two points on the Earth's surface. Actual sailing distances are longer due to land masses, shipping lanes, weather routing and traffic separation schemes. Coordinates are entered in Degrees and Decimal Minutes (DDM) format, which is the standard used on nautical charts and ECDIS systems.
Common Mistakes
- Entering minutes of 60 or above — minutes must be 0 to 59.999.
- Selecting the wrong hemisphere direction (N/S or E/W) — double-check your chart or GPS.
Frequently Asked Questions
What is Degrees and Decimal Minutes (DDM) format?
DDM expresses coordinates as degrees plus decimal minutes, e.g. 51° 30.444’ N. It is the standard format used in maritime navigation, ECDIS, chart plotters and VHF DSC distress calls. It differs from decimal degrees (51.5074°) and from degrees-minutes-seconds (51° 30’ 26.64”).
Is the great-circle distance the same as the sailing distance?
No. The great-circle distance is the theoretical shortest path. Actual sailing distances are longer due to land masses, weather routing, traffic separation schemes and port approaches.