The basic rules about suit styles and suit buttons…. they’re as easy as 1-2-3 (almost).
1. One-Button Suit Jacket
This is what you’ll wear with a tuxedo, generally to a black-tie event. Outside of such occasions, gents don’t generally get about in one-button suit jackets. When wearing, the rule is simply button the suit when standing and unbutton when sitting.
2. Two-Button Suit Jacket
This is the classic look, thanks to versatility that means it’s appropriate for social events and business. The very cut is flattering and you’ll immediately notice that a two-button suit makes you seem taller. As for buttoning up, the rule is: fasten the top button when standing and unfasten when seated. Never do up the bottom button.
3. Three-Button Suit Jacket
While less common than it was once, the three-button suit is definitely a choice shorter men should consider because the optics of the triple button layout makes you look seriously longer and leaner of body. The three-button suit tends to be more appropriate to business and serious events. Add a waistcoat and you’re decked out for a formal occasion. The rule of buttoning here is that the centre button should be fastened when standing. The top button is optional. The bottom button should never be done up. Undo all when seated.