A modern bachelor party may fall anywhere on the scale of very formal to quite casual. It is important to know what the evening may entail when determining how to dress. A plaid shirt and dark jeans are appropriate for a backyard barbecue bachelor party, they would not be appropriate for one that takes place in a casino or trendy nightclub.
For a bachelor party with friends, appropriateness comes first and comfort is a close second. This being said, it is important to avoid kitschy novelty tee shirts with phrases such as “dead man walking” and “what happens at a bachelor party, stays at a bachelor party.” You can find plenty of these if your search online but you should avoid them. No one really needs to advertise on his chest that it’s a bachelor party in order for all of you to have a great time.
If you are the groom at the bachelor party, you can set the standard for as formal or informal as you would like it to be. It is appropriate for you to discuss this with your best man (or whoever is planning the party for you) ahead of time, and to include an indication of this on your invitation. For example, if your bachelor party entails a night of poker and beer at a buddy’s house, a simple phrase such as “come as you are” can let your guests know that casual attire is appropriate. However, if you spending a night in Vegas and renting a limo, you may want to tell your guests to “dress to impress” or indicate “semi formal attire is requested.”
The majority of bachelor parties fall on the scale somewhere between casual and semi-formal. This means that it is appropriate for you to wear a slightly more stylish version of your daily wear, or what I often refer to as dressy casual. Try gray wool dress trousers, a white and gray pin stripe shirt, and a black skinny tie, which is currently one of the most modern and trendy tie styles. Other appropriate takes on “dressy casual” would be dark jeans with a button down shirt and a vest, or a colorful polo shirt with a sport jacket layered over top. If you are going to be bar hopping or clubbing, consider that you may wish to dress in layers to accommodate fluctuating temperatures. A button down shirt can easily be rolled up to your sleeves if needed. Or a sport jacket can be removed and hung on a chair back.
Because bachelor parties are normally evening events, faring on the side of dressy over casual is a good idea. You’ll notice that women often pull out their dresses and heels for evening events, and you should really try to match their level of sophistication. Give yourself a clean shave, and splash on some cologne. When you think you are finished getting dressed, go back and put on just one more accessory, such as a sterling silver watch, a pair of Wayfarer sunglasses, a leather cuff bracelet, or an orange silk pocket square. It is these little touches that take you from looking normal to looking party- ready.