If the ABV is 40% then 4/10 of the bottled liquid is alcohol.
Pour 250cc into a glass, 100cc is alcohol, 150cc basically water and taste additives.
Check the calculators - easy to use.
Bought locally, most, if not all, beer/lager bottles 'n cans actually state the number of alcohol units contained.
Just checked
Gordon's original special dry London gin for UK 37.5% BV 700cc bottle marked as 26.3 units 0.375 x 700 = 262.5cc alcohol divide by 10 = 26.25 or 26.3 units... Total fluid per unit 700 / 26.3 = 26.61cc - Not much is it?
But
'Gordon's original special London dry gin' bought at duty free shop (Amsterdam) 47.3% BV in 1 Litre bottle contains 473 cc of alcohol or 47.3 units thus 1000 / 47.3 = 21.14cc of fluid holding 1 UK unit... That old 'export' quality again hey?
Mas' I fink you are getting me 'at it' !