question about weighing scales

[angel_uk]

hiya. i want to know does anyone know how the weighing scales work?
i have simple ones with the option of flicking betwen kg/lbs/stones.
my question is why is it innacurate?
my start weight was 191lb that was on the same scales 13st10lb. then week later i lost 2 lb that took me down to 13st8lb but on the option where it shows just lb it was 190lb?
how does it work that when i use stones it takes 2 lb off and in full lb it takes just 1 off? surely 1lb is 1 lb. it shows 0.9 kg off for a lb so on both those options its exactly same.
anyone have an idea?

 

[angel_uk]

anyone?

 

[Pierce]

191lb is 13stone 9lb.

191/14 = 13.6428...

So thats 13 stone, now 13 * 14 (to get the pounds) =182lb

191lb - 182lb = 9lb

190lb is 13stone 8lb.

What could of happened is, if you flick from one display, lb to stone and lb, do you have to re-weigh yourself?

If so, then you could of just been on the edge of 13stone 9lb and 13stone 10lb.

Pierce

 

[angel_uk]

thanks for the great reply and your time

 

[Pierce]

Just glad to be able to help!

 

[rugbykirsty87]

Ive had this problem too. This morning i weighed myself and i was 12st 5.6.
I switched the scales to pounds and i was 174lbs and in kilos in 78.5kg so the pounds and thw kilos have me at 12st 3 but not the actual stones bit when i weigh on that setting