- One minute of latitude is one nautical mile (1.15 miles, 1.85 kilometers)
- One minute of longitude at the equator is also one nautical mile, but decreases as you move toward the poles.
You can find this by taking the Earth's circumference and divide it with number of minutes. Earth's circumference (the length of equator) is 40075.02 km.
40075.02 / 360 / 60 = 1.8553 km
One minute of longitude on equator is 1.8553 km. Please note - on equator (i.e. on 0 degree of latitude)!
Because the length of parallels decrease toward the north or south pole, the length (in km or miles) of minute of longitude differs for different latitudes. For example on polar circle (66°33'38" south or north) one minute of longitude is only 1.0035 km.
For latitude it's simpler - the length of all meridians are the same.
Take Earth circumference (the length of meridian) is 40007.86 km. Please note - Earth equatorial circumference differs from meridional, because Earth is not a sphere.
40007.86 / 360 / 60 = 1.8522 km
One minute of latitude is 1.8522 km.
For common life it's much to easier consider Earth spherical and use nautical miles.
One nautical mile is 1.852 km and it's approximately the length of one minute from meridional circumference.