Gradians to Mils (NATO) Conversion

Gradians

A gradian is equal to 1/400 of a revolution or circle, or 9/10°. The grad, or gon, is more precisely defined as π/200, or 1.570796 × 10^-2 radians.^[1]

This unit simplifies the measurements of right angles, as 90° is equal to 100 gradians.

Right angles in gradians

Gradians	Degrees
0 grad	0°
100 grad	90°
200 grad	180°
300 grad	270°
400 grad	360°

A gradian is sometimes also referred to as a grad, gon, or grade. Gradians can be abbreviated as ^g, and are also sometimes abbreviated as gr or grd. For example, 1 gradian can be written as 1^g, 1 gr, or 1 grd.

Mils (NATO)

A mil, short for milliradian, is equal to 1/6,400 of a circle. The mil used by the US military and NATO forces is slightly different than the true value of a milliradian, which is equal to 1/6,283 of a circle.

During World War I the US adopted what is now the NATO mil to replace degrees and minutes for use in artillery sights. They opted to round mils to 6,400 per circle for simplicity at the time. Today, the mil is commonly used to measure adjustment of sights and scopes of firearms.

There is rightfully much confusion as a result of the mil adopted by the US military and NATO being slightly different than the milliradian.

A mil is sometimes also referred to as an angular mil. Mils (NATO) can be abbreviated as mil, for example 1 mil can be written as 1 mil.