Draft beer lovers, we’ve got some good news and bad news. The good news: A new tool allows you to see how much beer you’re missing when a bartender doesn’t fill up your pint glass all the way. The bad news: You have to be a douchebag in order to use it.

Yes, the beer gauge costs $2 and works with any standard pint glass, allowing bar hoppers to check how many ounces of beer they lose on a given “short pour.” Often, that amount is surprisingly large due to the design of the pint glass. Because the glasses are wider on top than they are on the bottom, even a half-inch down results in a 13% loss. Instead of getting a full 16 oz., then, you get a mere 14.

But using the gauge to point out the disparity to the bartender risks making an ass of oneself. Besides, it’s often not the bartender’s fault. In order to fill the glass completely, she’d have to risk spilling beer everywhere and angering customers. The real problem, Beer Gauge creator Chris Holloway told the Wall Street Journal, is the design of US pint glasses

Ideally, a pint glass could hold more than 16 ounces and would be etched with a line near the top showing the level of a pint. “They actually figured this out in Europe,” Holloway said. “When you order a 0.3-liter or 0.5-liter beer in Europe, the glasses have 0.3-liter or 0.5-liter marks etched on them, and the volume of the glass extends past these etch marks. When the beer is served, they fill the liquid to the 0.3-liter or 0.5-liter marks and the head can then fill the remaining volume in the glass. Thus, you get the amount of beer liquid you paid for.”

Until then, the only way to get your money’s worth is to ask the bartender for a full fill. Have fun with that.

Using Math to Keep Pint Glasses Full

The Beer Gauge [official web site]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.