That is as practically awkward as it sounds: participants pressed “start” at penile penetration and “stop” at ejaculation. You may note this could affect the mood somewhat, and might perhaps not exactly reflect the natural flow of things. But – science is rarely perfect, and this is the best we’ve got.
So what did the researchers find? The most striking result is that there was a huge amount of variation. The average time for each couple (that is, averaged across all the times they had sex) ranged from 33 seconds to 44 minutes. That’s an 80-fold difference.
So it’s clear there’s no one “normal” amount of time to have sex. The average (median, technically) across all couples, though, was 5.4 minutes. This means that if you line up the 500 couples from shortest sex to longest sex, the middle couple goes for an average of 5.4 minutes each time they do it.
There were some interesting secondary results, too. For example, condom use didn’t seem to affect the time, and neither did men’s being circumcised or not, which challenges some conventional wisdom regarding penile sensitivity and its relationship to staying power in the sack.
It didn’t much matter which country the couples came from either – unless they came from Turkey, in which case their sex tended to be significantly shorter (3.7 minutes) than couples from other countries (Netherlands, Spain, the United Kingdom, and the United States). Another surprising finding was that the older the couple, the shorter the sex, contrary to the prevailing wisdom (probably peddled by older men).