Why Do Suits Have Two Buttons?
It’s not an absolute rule—three-button and one-button suits are out there—but when it comes to single-breasted suits, you can expect to find two buttons nine times out of ten. It’s been that way since about the 1920s, when more casual dress codes and the rise of the automobile saw longer, three or even four button-jackets go out of style.
Naturally, a jacket with two buttons begs the question: when to button what buttons, and why?
When to button the top button
The top button is the sole button meant to be closed. Because the top button tends to sit around the navel, closing it helps to create the “V” shape a properly fitting suit should should have. But aside from creating that more flattering look, it’s also more formal. If you are wearing your suit to a business occasion, wedding, or funeral, the top button should be buttoned whenever you are standing. However, no one expects you to have that top button buttoned while you are sitting down.
When to button the bottom button
You should never button the bottom button. This may sound like a wildly counterintuitive piece of advice at first. After all, why would tailors go to the trouble of adding a second button if it can’t be used?
The truth is that the second button is only meant to play a decorative role and balance the suit’s silhouette (it may have also been abandoned because of a British monarch’s buttoning preferences). If you close it, it will cause the bottom of the jacket to hug the hips rather than drape outward, which spoils the “V” shape you’re looking for. Just say no to the bottom button.
When to button neither button
Neither button should be buttoned if you’re seated, of course. But if you happen to be wearing a suit jacket casually—for instance, with khakis and a shirt without a tie—or to a casual work place or event, you shouldn’t feel pressured to close that top button at all times.