Q&A for How to Size an Overcoat

If you're going to wear an overcoat over heavy layers like a blazer, you'll need extra room. However, to avoid looking like you're wearing someone else's clothes, make sure the coat fits you well in the sleeves and shoulders.

The same: either a 42S or 42R. Most overcoats are pre-measured to fit over a suit, so shop for the same size you normally wear.

You would likely need a large or XL depending on the brand's cut, etc. I would suggest trying the clothes on or ordering from a provider who allows free returns.

Read the very thorough instructions above. If you're a man, you would need to shop for the same size trench coat as your normal suit jacket size, because trench coats are sized to fit over the man's suit. It's a good idea to wear a suit coat or a sports coat when you are trying on prospective trench coats at the store. If the trench coat you're looking at only comes in sizes like S, M, L, XL, then you can start by matching to the normal coat size you regularly wear, and just size up if it doesn't seem to fit over your suit coat or sports coat. Obviously, if you never plan to wear your trench coat over a business suit, you should just match to your normal coat size or its numeric equivalent.