This is generally a good rule of thumb if you’re trying to monitor your consumption, but this rule also becomes fuzzier the more you drink. Unless you have one beer and then wait an hour (cause anyone would ever do that), then the science of things gets a little more twisted. As you continue to drink, the equation grows somewhat exponentially. A good rule of thumb is to add 30 minutes per beverage you have in that original time frame. For example, if you have six drinks in 15 minutes, (IT WAS LAST CALL!), you could be looking at 9 hours to sober up completely.