Updated: Jul 8, 2020
The dress code for an interview is business formals.
For men, it includes:
Suit (a blazer and a trouser) - most commonly preferred colours are black, blue and grey in that order. It is recommended that you wear the same coloured blazer and trouser as it looks more formal.
Shirt (full-sleeved) - it should be a collared shirt and the colour should be in accordance with the colour of the suit. For a list of the best combinations, have a look at this link.
Tie - the ones that are most commonly used are red, blue, grey and brown. Again, for matching it with the shirt and the suit, refer to the above link.
Formal Shoes - mostly, they are leather shoes available in the black, brown and camel colours. You may choose black to be safe, else can refer to this guide for matching:
Hair - get a hair-cut and trim your beard if you keep one.
Accessories - Please wear a wristwatch if you have one. It can be metallic or one with a leather strap.
Some candidates prefer not to wear a blazer, but they are very less in number so unless you have a strong reason not to wear it, you should wear one, it looks better.
For women, it includes:
Suit (a blazer and a trouser/skirt) - the details are the same as above.
Shirt - same as above
Bellies - they are the most ideal footwear as they are comfortable and go well with the suit. Please note that the footwear should have the toes covered. The most commonly preferred colours are black, brown and tan. Avoid heals or choose to go with wedges as they’d make much lesser noise.
Hair - there is no rule that says that you can’t keep your hair untied during an interview, the only rule is that they shouldn’t be covering your eyes. So, cut your fringes to be safe.
Accessories - wear as less jewellery as possible. It shouldn’t be flashy. Wear a wrist-watch that goes well with your suit. You won’t have to carry a handbag inside, so you may carry a laptop bag instead.
Some candidates also wear traditional that includes sarees or salwar-suits, but they are very less in number. You may wear it if you feel more comfortable with it.
One thing that I carried with me for all the interviews was a black leather folder to hold all my documents. It looks very elegant if the folder is a complement to your attire. You may choose it over a clear-bag that is generally used.
You may also like to read more about IIM Interviews.