A U.S. "standard" drink contains about 0.6 fluid ounces or 14 grams of "pure" alcohol. That's the amount in 12 ounces of regular beer, 5 ounces of table wine, or 1.5 ounces of 80-proof distilled spirits.
A “standard drink” size is not always a customary serving size. But knowing standard drink sizes can help you to compare the strength of different drinks and to know when you’re within or over healthy drinking limits.