Well, here in the UK, we officially use mainly metric measurements, but some old school members still like to use imperial measurements.
And of course our friends in the US of A generally like to use imperial measurements.
I always try to use both imperial and metric when am doing posts and things so that everyone understands rather than having to convert measurements.
Also having both measurements means there is less chance of making a mistakes in dosing or for med treatments
I know it can be confusing
But this Forum has a handy calculator for converting measurements for all sorts of things, I use this quite often -