Common conversions
1 kg = 2.2046 lb · 1 lb = 16 oz = 453.59 g · 1 stone = 14 lb · 1 tonne = 1000 kg
Strictly, these convert mass, not weight — mass is constant everywhere, while weight is mass × gravity. In everyday use the terms are interchangeable on Earth. The kilogram is the SI base unit; the US/UK pound is defined as exactly 0.45359237 kg.
Converting weight units
Every unit is defined relative to the gram, so one input converts to all units at once — metric (mg, g, kg, tonne) and imperial (ounce, pound, stone). Handy reference: 1 lb = 453.59237 g, 1 kg ≈ 2.2046 lb, and 1 stone = 14 lb.