What to wear on the first day of a new job (when you don't know the dress code yet)
The first-day outfit has an impossible brief: you do not know the dress code yet, and you cannot ask without feeling awkward. The answer is an outfit that reads correctly at every formality level, plus ten minutes of research that removes most of the guesswork.
The research you can do tonight
Check the company's LinkedIn and Instagram for photos of the actual office - team pages, event shots, office tours. What employees wear in unstaged photos is the code. Your interview memory is data too: what did the people you met wear? Match the most formal person you interacted with, then soften one notch.
The universal first-day outfit
One formula survives every office: tailored trousers in navy, charcoal, or black; a clean knit or crisp button-down; a structured third piece - blazer or quality cardigan - you can remove; and polished leather shoes. Every element reads business formal assembled and business casual with the blazer off. That removable layer is the whole trick: you calibrate in the lobby bathroom if you misread the room, in either direction.
Why not a suit
A full suit is unrecoverable - if the office is sneakers-and-hoodies, you are 'the suit' until at least week three. An overdressed separates outfit sheds its top layer and becomes fine. Under-dressing is the worse error but the rarer one; the separates formula protects against both directions of mistake.
The details that carry the signal
Fit and condition outrank formality: pressed, lint-rolled, polished shoes, nothing pilled. A simple, neat outfit reads as competent at any code level; a rumpled expensive one reads as careless. Skip anything that needs adjusting all day - day one is not the moment for a blouse that gapes or shoes that pinch by 2pm.
Day one is reconnaissance
The real goal of the first outfit is to be forgettable enough that people remember you, not it. Watch what your team actually wears for a week - the gap between the official handbook code and the practiced code is always real - then build your office wardrobe to the practice, not the policy. By week two you will know whether the blazer ever comes back.