Bar Knowledge

International Pour Measures

Ounce conversions, regional pours and alcohol calculations.

3 min read

Serving size differs from a unit

An ounce is a unit; single and double are serving labels that depend on location and venue. A standard-drink definition is different again and is not a safe-consumption allowance.

Volume conversions

US and Imperial fluid ounces differ. Cocktail oz usually refers to the US system; confirm the source when unclear.

Volume conversions

1 US fl oz	29.5735 ml
1.5 US fl oz	44.3603 ml
2 US fl oz	59.1471 ml
1 Imperial fl oz	28.4131 ml
2 cl	20 ml
5 cl	50 ml

Regional practices

These are example practices, not universal national legal quantities. Great Britain has serving rules for specified spirits; verify current local law.

Regional practices

Great Britain	25 or 35 ml; multiples	Rules for specified spirits
USA	1.5 fl oz ≈ 44 ml	Common; venue-dependent
Germany	2 or 4 cl	Common, not universal
Türkiye	Some venues use 4–5 cl singles	Confirm product and venue standard

Ethanol calculation

Ethanol volume = serving ml × ABV / 100. A 50 ml pour at 40% contains 20 ml ethanol, about 15.8 g using approximately 0.789 g/ml density. Include liqueur and vermouth separately. Dilution lowers concentration, not total ethanol.