Kilograms is weight, Newtons is mass, they are different. Weight depends on gravity
345 pounds = 156.489368 kilograms
Since there are 1000 mg in 1 gram, and 1000 g in 1 kg, there are (1000 x 1000) mg in 1 kg, which is 1,000,000 mg in 1 kg. Or conversely, there are 0.000001 kg in 1 mg (that's 10-6 kg)
1 kg = 1000 g. Therefore, 4301 g = 4.301 kg.
45.45kg.
1kg