If you are having difficulty working out the volume of drink you have had, there are approx. volumes shown below for standard drinks.

Soft drinks purchased will generally have a volume stated somewhere.

Standard mug of coffee/tea225ml
Tea cup of coffee/tea150ml
Small/Large Glass of wine125ml/250ml
Spirit with Mixer200ml

 

Coffee shop drinks
Regular Americano/Latte340ml
Regular Cappuccino300ml
Large Americano/Latte450ml
Large Cappucino420ml
Expresso227ml
Regular Milk shakes/Frappe340ml