[eadmund]

A 12 oz is .34 L, which at 5% would be 1.7 units of alcohol — rather different than a single unit.

[volkl48]

In the US, "units of alcohol" are not a thing or part of the government recommendations.

One standard drink in the US is tied to 12oz of 5% beer (or it's equivalents in wine/spirits), not the UK definition of a "unit" of alcohol.

When there are US health recommendations made, they are referring to standard drinks.