Nautical Miles Calculator

Distance Map measures distances in nautical miles for maritime routes and flight planning. Plot passage between harbours, lay waypoints for a sailing trip, or calculate a great-circle flight distance — all with proper nautical units.

What Is a Nautical Mile?

A nautical mile is 1,852 meters — exactly one minute of latitude. It’s the standard unit for marine and air navigation because it ties directly to the coordinates on a chart:

• 1 nautical mile (nmi) = 1 minute of latitude
• 60 nautical miles = 1 degree of latitude
• 1 nmi ≈ 1.151 statute miles ≈ 1.852 km

Speed at sea and in the air is measured in knots — nautical miles per hour.

How to Measure Nautical Distance

1. Open Distance Map
2. Switch units to nautical miles
3. Drop pins at each waypoint — harbour, headland, way-mark
4. See total distance in nmi
5. Add legs for multi-stop passages

For Sailing and Motor Boating

Passage planning — Lay waypoints around hazards, calculate total passage distance, and work out time at a given speed in knots (distance ÷ speed = hours).

Coastal navigation — Measure distance between lighthouses, buoys and bearings. Great-circle segments at sailing scales are effectively straight-line, which matches chartwork.

Fuel planning — Motor-sailing at 5 knots over a 60 nmi passage is 12 hours of engine time. Plan fuel reserves accordingly.

Tides and currents — Knowing exact distances helps calculate CMG (course made good) against tidal flow.

For Aviation

VFR flight planning — Measure great-circle distance between airfields to estimate fuel and flight time.

Waypoint distances — Drop pins at VORs, NDBs or named fixes to calculate leg distances.

Cross-country planning — Multi-leg flights with accurate distances at each point.

At aviation scales, great-circle (geodesic) calculation matters — Distance Map uses WGS84 geodesic math, so long-distance flight paths are accurate.

Great-Circle vs. Rhumb-Line

Distance Map calculates geodesic (great-circle) distance, which is what you want for route totals. For heading-to-steer, use the chart.

Unit Conversion

Switch instantly between:

• Nautical miles (nmi)
• Kilometers (km)
• Statute miles (mi)
• Meters / feet for altitude

No need to re-enter a route to change units — everything is converted on the fly.

Export for Your Chartplotter

Every route can be exported as GPX, compatible with:

• Garmin chartplotters
• Raymarine Axiom
• B&G Zeus / Vulcan
• Navionics Boating
• Aviation EFB apps (ForeFlight GPX import, etc.)

Try It

Plan your next passage or flight with Distance Map. Free on iOS, and the web distance calculator supports nautical miles too.

Get Distance Tool

Download Distance Tool for iOS and start measuring in seconds.