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How To Select The Right Suit Size Online

by Zoey Parker 01 Feb 2020

 Getting the right size suit has always been a challenge for me I like to classify suit buyers into 2 categories the first is the experienced suit buyer, he knows exactly what size to buy and knows the perfect fit because this category of suit buyer wears suits on a regular basis for work and is no big deal. I fall into the second category which is the occasional suit buyer, I love suits don’t get me wrong but unfortunately never have the opportunity to wear one so when I do get the chance to wear a suit for a wedding, dinner party, function or a funeral I never know what size I need to buy because the suits I owned in the past either no longer fit or the wife has thrown out due to how old it was! This article is for anyone that sits in this category or simply wants some advice on getting the fit spot on because getting the size right is just as important as the style and look of the suit:

  1. Sizing of suits comes as 2 main components the upper body which consists of a blazer/waistcoat and then the trousers. Unlike jackets and tops which size up as S, M, L… the sizing for suits in the UK come as numeric values which usually start at 34 and go up to 52 these numbers simply represent the total chest size in inches “ so a 42 would fit someone with a 42” Chest.

Common question: do I need to go for a slightly bigger blazer jacket if I am wearing a waistcoat underneath?

Answer: No, all suit manufacturers already take this into consideration and the waistcoat will always fit snug to allow for the blazer to fit comfortably over this so you will usually want to buy the same sized blazer and waistcoat.


Suit measurement of blazer size



  1. To work out the exact chest size you need the best way to do this is by taking the size from another blazer or suit you own as this will give you the accurate size you need. If you try measuring your chest this can sometimes go wrong and I would not recommend this as it has a lot of room for error such as how tight you are taking the measurement or where exactly are you taking the measurement from.

Common question: I don’t own a suit/blazer that fits well, how do I now work out my size?

Answer: my advice would be to go visit a local shop to try on a blazer and when you find the size that fits well simply keep a note of it and refer to this size when buying online.



  1. Now that we have sorted the first part of the suit its time to ensure the trousers that come with the suit also fit right. The trousers for suits are also sized in Inches “ in the UK this is usually easy as most trousers/jeans are also marked in the same way so my advice is simply select the same size that you usually wear or a size bigger as sometimes jeans can have 1-1.5 inches allowance, which is never the case with suit trousers, if the label states 34, it's exactly 34 inches.

Common question: The suit I am looking at is sold as a set and the trouser size I need is different from the blazer size that comes in the set.

Answer: 90% of the time the sets fit spot on but if you have an athletic build or a slightly odd-shaped body then the ‘standard’ set size may not work, if the trousers size is 1 size up or down to the blazer size then usually the set will still work, my advice here goes bigger rather than smaller and you should be fine. If you do fit into the category of being athletic built or an odd shape and the set you need is totally off then you need to opt for a suit that has a ‘trouser swap’ option this way you can select a different sized trouser to the one that comes in the set.



  1. Suit Lengths – some suits come in different lengths S (Short), R (Regular) and L (Long) this is simply to do with the length of the suit and not the fit (I will get into the fit of suits in the next point) if the suit you're looking at makes no mention of the length then it will be a Regular by default, Regular length again will fit 90% of guys however if your exceptionally tall or exceptionally short you will want to consider a ‘Short’ or ‘Long’ fitting suit.

Common question: the suit I really like does not come in short/long and this is the fitting I really need.

Answer: no need to worry, all suits have additional fabric in the sleeves and also the trousers to be let out to a ‘long’ this can be done at most dry cleaners for a charge usually around £10 for trousers and £15-£20 for sleeves, to make it shorter is no problem also as simply needs to be cut down and the charges are the same.

Top Tip: If you have long arms instead of extending the sleeves out simply wear a double cuffed shirt this way it sits perfectly with slightly shorter suit sleeves



  1. Suits come in 4 common fits they are as below:
  • Regular Fit – this is the traditional fit whereby the suit does not have much of a shape to it.
  • Tailored Fit – This is my favorite fit as it is in between a slim & regular fit, the suit has a good shape to it, sits nicely on most body shapes and is true to size.
  • Slim Fit – This fit has a more fitted feel to it and works really well for someone that has a more athletic build.
  • Skinny Fit – This fit is not very common but works well for someone that has a small/skinny body frame as it the fit work better (this fit is not recommended for larger guys)


Once you have got the suit size spot on don’t forget about all the other components and accessories to complete the look, check out our range of shirts, ties, shoes, belts, hats, and overcoats

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