1 mg equates to 0.015432 grains.
How many grains equal 0.4mg ?
8.1 mg, approx.
1/150 grains = 0.432 mg
1 gr(grain) is equal to about 1/64th of a mg so 1 mg(milligram) is equal to 0.0154323584 gr(grains)
0.4 mg equates to about 0.0061729 grains.
0.4 mg = 0.0061729 grains.
14 mg is 0.21605 grains.
45 mg = 0.69446 grains
647.9891 mg
10 grains is 648 (647.99) mg
A grain is an old-fashioned, medieval unit of weight equal to the weight of a grain of wheat or barley, it isn't used in the modern world. One grain was roughly equivalent to 64.8 milligrams, so 7.5 would be 7.4 time 64.8, which is 486 milligrams, or 0.486 grams.
0.4mg is 0.0061729 grains.