How big is a fifth in drink measurements?

Question

We have a different system in the UK. What would it equate to?

I was reading a story on golfer John Daly who claims to have drank a fifth of whiskey every day during the year he was 23 years of age.....

Answer 1

A 750ml bottle...that's a fairly good amount!

Answer 2

It is one fifth of a gallon 25 ounces

Answer 3

appx 750 ml, the name comes from the volume being 1/5 of a gallon

Answer 4

A fifth is one fifth of a gallon.

Answer 5

750mL