If you are like me and having trouble figuring out exactly how to measure units (I think we U.S. folks - or at least this one - don't measure in units.) here is a formula from Wikipedia on how to do that:

FormulaThe number of units of alcohol in a drink can be determined by multiplying the volume of the drink (in millilitres) by its percentage ABV, and dividing by 1000. Thus, one pint (568 ml) of beer at 4% ABV contains:

\frac{568 \times 4}{1000} = 2.3\mbox{ units}

568 x 4% divided by 1000 = 2.3 unitsThe formula uses the quantity in millilitres divided by 1000; this has the result of there being exactly one unit per percentage point per litre of any alcoholic beverage.

When the volume of an alcoholic drinks is shown in centilitres, determining the number of units in a drink is as simple as multiplying volume by percentage (converted into a fraction of 1). Thus 75 centilitres of wine (the contents of a standard wine bottle) at 13 % ABV contain:

75 \times 0.13 = 9.75\mbox{ units}

Quantities

It is often stated that a unit of alcohol is supplied by a small glass of wine, half a pint of beer, or a single measure of spirits.[2] Such statements may be misleading because they do not reflect differences in strength of the various kinds of wines, beers, and spirits.Beers A half pint (284 ml) of beer that has a strength of 3.5% abv contains almost exactly one unit. However, most beers are stronger. In pubs, beers generally range from 3.5% to 5.5% abv with continental lagers starting at around 5% abv. A pint of such lager (568 ml at 5.2% for example) is almost 3 units of alcohol, rather than the often-quoted value of 2 units per pint.

A 500 ml can/bottle of standard lager (5%) contains 2.5 units.

'Super-strength' or strong pale lager may contain as much as two units per half pint.

One litre of typical Oktoberfest beer (5.5% to 6%) contains 5.5 to 6 units of alcohol.

Wines A medium glass (175 ml) of 12% abv wine contains around two units of alcohol. However, British pubs and restaurants often supply larger quantities (large glass: 250 ml) which contain 3 units. Red wine might have a higher alcohol content (on average 12.5%, sometimes up to 16%).

A 750 ml bottle of 9.5% abv wine contains 7.125 units.

A 750 ml bottle of 12% abv wine contains 9 units.

A 750 ml bottle of 12.5% abv wine contains 9.375 units.

A 750 ml bottle of 13% abv wine contains 9.750 units.

A 750 ml bottle of 13.5 abv wine contains 10.125 units.

A 750 ml bottle of 14.2 abv wine contains 10.650 units.

A 750 ml bottle of 14.5% abv wine contains 10.88 units.

Some port wines may contain 20% abv or more, which is 15 units of alcohol per bottle.

I added some of the calculations for your reference. You can see the whole article here:

http://en.wikipedia.org/wiki/Unit_of_alcoholI will now be adjusting my units!!!