Depends on the drink
Standard drink has 14 gms pure alcohol
beer (5% alcohol)-12 oz
malt liq (7%)-8-9 oz
wine (12%)-5 oz
hard liquor/spirits (80 proof/40%)-1.
5 oz (jigger)
mixed drinks can vary- depends how well you know the bartender, so be careful, especially if you plan on driving later.