Distance

IG name   IG equivalent  RL equivalent
=========================================
step      1 tile         ~1 meter
mile      1 map          in theory ~1.5 km, in practice only ~100 m

Weight

IG name   IG equivalent   RL equivalent
=========================================
stone     #               ~10 gram
#         a man's weight  ~75 kg

Liquid volumes

IG name   IG equivalent               RL equivalent
=====================================================
Bottle    an average potion bottle    1/2 liter
Barrel    an average barrel           100 liter