Use this cartographic calculation to convert, scale, or compare map, terrain, bearing, raster, or route quantities when the coordinate and unit conventions are explicitly known.

Statute Miles (mi)

Required number input.

International nautical miles from international statute miles (1609.344 m and 1852 m respectively). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Nautical Miles (nmi)

The resulting nautical miles returned as a number.

• Map calculations depend on datum, projection, latitude, scale definition, magnetic-declination epoch, and whether distances are planar, rhumb-line, or geodesic. A compact formula cannot remove distortion or infer the missing reference system.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Confirm the map datum, projection, scale, and bearing convention before applying the result. Use geodesic or GIS software with current reference data when survey-grade or navigation-critical accuracy is required.

• Nautical Mile Minute Arc Converter

  Length in kilometres of a supplied number of international nautical miles (1852 m each); useful for approximate chart-minute scales.

• Back Bearing Calculator

  Reverse azimuth, normalized to [0,360), from a forward azimuth in degrees.

• Contour Density Per Cm Checker

  Number of contour crossings per map centimetre from a count along a measured map transect.