The International pound ( 0.45359237 kilogram ) is used in :
United States of America (USA) , South Africa, United Kingdom (UK) and the Commonwealth of Nations.
A rough guide when you are measuring liquids: 1 ml of water equals 1 gram, 1 litre of water weighs approx 1 kg - other liquids may differ.
Converting grams into ounces, the arithmetics
Grams times 0.0353 equals ounces
3454 g = 121.9262 oz
Answer = int(3454 * .0353) [121 oz]
The arithmetic to convert ounces to pounds and ounces is below
oz_start = 121
lb_calc = int(oz_start/16) [therefore lb_calc == 7 lb]
oz_calc = 121 - (lb_calc * 16) [therefore oz_calc = 9 oz]
Answer = lb_calc, oz_calc [7 lb, 9 oz]
Wikipedia links covering units of mass show/hide