Firstly what do u mean by a stone? Why do people say that they want to lose 2 stone (just an example)??
We used to use pounds in the UK (lb) and stones, which is 14 pound. I think in the 70s we changed to kilograms. So 1kg is 2.2lb
Most of the country is still mixed up using a combination of them all...wasnt a smooth change and even involved breaking laws to buy and sell veg . I mean wtf is 5lb of spuds in kg...I've no idea but can still hear my mum shouting me to get 5lb of spuds