Most modern suits have a single-breasted jacket. How to button it depends the number of buttons the jacket has.
One Button Jacket
- The jacket of this type of suit is distinguished by the presence of only one button.
- Because of its origins in traditional evening wear designs, one-button suit jackets are often cut longer than other types of suits.
- Keeping the button fastened maintains a balanced proportion.
- The issue of deciding which button to fasten is eliminated by the presence of only one button hole on the suit's jacket.
– These jackets should ALWAYS be buttoned when standing.
Two Button Jacket
- The top button on these jackets should ALWAYS be buttoned when standing.
- Unbutton the jacket only when sitting down to avoid creases. Fasten it again as soon as you stand up from your seat.
- NEVER button the bottom button.
Three Button Jacket
– Closing the top button on these jackets is OPTIONAL when standing.
– The middle button on these jackets should ALWAYS be buttoned when standing.
– The bottom button should NEVER be fastened.
– Undo all buttons when seated.
Double-breasted jackets are almost always worn buttoned. It's very unusual to unbutton one.
Double-breasted jackets are described with the total number of buttons on the suit front followed by the number of working buttons. A “six-on-four” jacket has six buttons but only four buttonholes.
Button all the buttons that have working buttonholes.
If you plan to leave some buttons undone, it is most traditional to fasten the top button.
However, men who prefer a longer line have been leaving the lowest button undone, including members of the British royal family, so you're probably safe either way.
