How to Measure and Understand Men’s Suit Sizes Like a Pro

Are you wondering how suit sizes work? Wonder no more! Today we’ll be taking a look at suit sizes for men. We explored suit jacket sizes in our article on how to understand a suit size chart, and we’ve filled you in on dress shirt sizing too. We’ve also taken an in-depth look at how to get perfect suit measurements for each body part. But how do you assess if a suit fits right? How do men’s suit sizes fit the equation? The Oliver Wicks experts have everything you need to know.

brown suits on mannequins

How Should a Suit Fit?

We explained everything you’ve ever wanted to know about fit in this article. However, in broad strokes:

  • Your pants should be form-fitting and ideally they would stay up without a belt while still allowing you to sit and move.
  • The “break”—the fold in the fabric of the pant leg that sits on top of the foot—can vary, but there shouldn’t be too much fabric bunching, or too little ankle coverage. Personal preference plays a large role in the pants break, within reason.
  • Suit shoulders might vary depending on style fit but should always follow the lines of your actual shoulders. No dimpling or excess fabric should be visible.
  • Your collar should lie flatly and comfortably. There should be no pulling or puckering, no popping up of the collar, no gaping as you move, and no using your tie or bowtie to force the fit. 
  • The top button of the jacket (with a 2-button design) should sit roughly about 1-3 fingers aboveyour belly button. The jacket should close with no puckering, but take button stance with a pinch of salt, as it can vary on the cut and styling of the jacket.
  • The sleeve length should stop just before the wrist break and show about ¼” -1” of shirt cuff beyond it. Of course, this is based on the assumption that your shirt sleeve is correctly finishing at the bone of your wrist.
  • The jacket length should be to the second knuckle of your thumb, and fully cover your rear end, but not hang below (that’s more like an overcoat). There is some variation between styles, but that’s an excellent place to start. 
  • There should be no puckering, pulling, or excess fabric at your jacket chest or back. You should be able to move comfortably without the jacket straining, even when buttoned. A great fit will compliment the wearer's silhouette.

Understanding Suit Sizes

How do you measure a suit size from your actual measurements? The numbers on a suit size don’t directly correlate with physical measurements, so how do they work?

Just quickly, we’ll explain why body measurements and garment measurements are different: If a suit was tailored exactly to your body measurements, it would be a skin-tight fit - Great for a stretchy sportswear underlayer, but not for a suit.

We take body measurements and add a calculated amount of additional fabric, which is called ‘ease’. Don’t worry about having to calculate the ease yourself - That’s our job as tailors, and we have systematic pattern formulas specifically for this in order to achieve the desired cut - It’s not guesswork.

The Basics

If you look at the size label of a suit, you will most likely see a double-digit followed by either S, R, or L. For example, 38L. The first number is the jacket chest size (which won’t always match your actual chest measurement). The second is the jacket length.

Below you’ll find an example of a fairly standard size and conversion chart for suits. Not all brands will fit this exactly, so always look for a brand-specific one, but this should give you an example. 

As you can see, You have the size on the actual label, some “equivalent” sizes to help guide you, and the raw measurements that size should fit.

Please note that European suit sizes are not standardized like suit size charts suggest—suit measurements can vary wildly between different countries, from Italy to France, to Germany or the UK. “Euro Size” is more its own sizing system rather than a reflection of standard European sizing. US sizes are easier to understand, as you’ll see that the size IS designed to match up with your chest body measurement, but don’t rely on it.

 International  US Euro Chest (“) Waist (“)  Arm (“)
 S  34 46 34 28 31.5
 S  36 46 36 30 32
 M  38 48 38 32 32.5
 M  40 48 40 34 33
 L  42 50 42 36 33.5
 L  44 52 44 38 34
 XL  46 54 46 40 34.5
 XL  48 55 48 42 35
 XXL  50 56 50 44 35.5
 XXL  52 56 52 46 36


The sizes progress linearly in standard jumps. The numbers are based on an aggregate of men’s averages, which can be useful as a rough guide. However, men’s bodies vary considerably, and it can be difficult to translate loose averages into sizing for a real, actual person, which can make measuring suit sizes painful. 

Get the Best Fit

To find the best fit in an off-the-rack suit, always fit the standard specs as best you can, to the closest match, and fit the parts that can’t be altered—namely the shoulders, collar, length of the jacket and the waist on the pants—as the priority. If you have a 28.5” waist or a 34.35” arm, for example, round the measurement to the closest figure—a tailor can tweak the fit, but they can't add fabric magically! Remember that pleated pants are always a bit roomier than flat-front trousers.

What we’re saying is - If in doubt, or between sizes, size up… but use the shoulders as the most important factor to fit right off-the-rack.

The Standard Drop

Likewise, off-the-shelf men’s suit sizes don’t allow for physiques with too much variance in pant and jacket size. They use a “drop” to match a specific pant size to a specific jacket. The standard drop is 6 inches, so a size 38 jacket would have size 32 pants. Again, this is assuming the exact average body, which almost nobody has. If you don’t match that standard, made-to-measure is a better option for you.

‘Drop’ is also a word used to describe the level of tapering in a jacket. This is essentially the difference between the chest and jacket waist. A low drop will offer a relaxed fit, whereas a higher, more aggressive drop will be targeting more of a slim fit, as the jacket will cut in closer at the waist to show-off a trim body shape.

Most store bought suits tend to lean on a relaxed drop, on the basis that it will fit more people, and also those wanting a slimmer fit can have the waist brought in by a tailor. It’s almost always easier for a tailor to take in fabric than it is to let out.

The Lengths

Suit jackets usually come in three lengths: Short (S), Regular (R), and Long (L). You may sometimes also see XS and XL. This refers mostly to the sleeve length, but it may also affect the overall jacket length (depending on the brand). As mentioned, the lengths of a suit jacket are not easy to alter (especially if it’s a high-quality jacket with functional sleeve cuffs), so be aware of that when shopping off-the-rack. 

a dark suit with a bowtie

How to Measure Your Suit Size

What are the steps to measuring yourself for a new suit? Our other fit guides provide more in-depth information, but here are the basics.

Don’t struggle needlessly with this! Our videos are easier to understand than text!

If you’re after a practical guide, with instructional videos, we’d suggest creating an account on our site (free of charge, with no purchase obligations). Here you’ll be able to access our measurement videos, which walk you through every step of measuring in an easy-to-follow process that can have you measured from head to toe in 15-minutes or less.

Jacket Measurements

The jacket is the anchor piece of your whole look, and it’s important the fit is precise. When you’re trying to learn how to measure your suit size, this is where it counts most! While suit alterations can make a great fit into a perfect fit, they can’t do much if there are fit issues in the shoulders, jacket length, or collar, so focus on getting your best match there. Arm length can be altered, but only marginally, so aim to get as close as possible before you leave the store (within ½”). Here are the key things to keep in mind when bringing out your tape measure: 

  • Chest: Stand loosely and naturally. Don’t puff up the chest. Measure under your arms, around your chest at the point right across your nipples. Don’t pinch, but don’t measure too loosely - Aim for ‘snug’, with the allowance of roughly a finger under the tape. This is often easier with a friend or family member as an assistant, to ensure that the tape is held level all the way around your torso.
  • Sleeve: Pull your friend back into the room! Find a closely-fitted shirt to make it easier. The seam of the sleeve should sit at the point where your shoulder finishes, not down the arm or up onto the neck or shoulder. Stand relaxed and natural. Measure from the seam down to the second knuckle of your thumb. In a standard suit, you’re stuck with the sleeve length you get (pretty much), but a made-to-measure suit can use this measurement to help you get the perfect fit.
  • Shoulders: On the same shirt, measure seam to seam straight across the back, from shoulder to shoulder. Again, this won’t help with a standard size, but can help you understand your shape and the measurement is needed for made-to-measure tailoring.

Word salad? You may prefer our website videos for a more visual experience.

What Jacket Length Am I?

Use your height combined with your chest measurements to figure out which of the three standard lengths you fit. Roughly speaking, men at or under a height of 5’ 7” with a chest measurement between 36-46” will need a short, men who are 5' 7” to 5’11” with chest measurements between 36-54” will need a regular, and taller men will always need a long.

If you have unusual proportions, it’s best to try a jacket on if possible to check the fit for yourself. If everyone could get a perfect fit from ready-to-wear suits, well, we’d likely be out of business, as there’d be little need for made-to-measure, aside from the design customization and high-quality fabric options. Back to the point we’re making though, for the vast majority of people, off-the-rack suits involve a compromise on fit in some way or another, but use jacket length as a fit aspect that you’ll want to prioritize.

Pant Measurements

Pant waist size is more important than pant leg length, again due to the difficulty of tailoring, so focus there first.

  • Waist: Measure at your belly button for higher rise trousers, and two to three fingers below it for low-rise. Allow for a generous, but not baggy, fit from the tape measure. Don’t let the waist measurement drop assuming your slacks will too! It’s better to use a solution like suspenders to help you offset your physique and keep your pants at your waist rather than wearing your trousers in the wrong place. If you don’t plan to wear a belt, or are fitting for a tuxedo, be very precise, as this measurement is needed for the right fit.
  • Hips: Wrap the tape around the widest part of your buttocks, ensuring that the tape is nice and level all the way around. Put two finger under the tape for a snugg but not tight measurement, and add a smidge. You don’t want to end up tight in the hips, as this causes all kinds of issues including pocket flare, poor drape, and even embarrassing ripping at the buttocks if you’re particularly unfortunate.
  • Outseam Length: For a made-to-measure garment, you need the length from the top of your trousers to the point where you’d like your suit pants to end. If you have any doubt, add a little.
  • Inseam Length: This measurement is particularly useful to determine the point at which you prefer the waistband to sit on your hips/waist. We’ll take the inseam, minus it from the outseam, double it, and boom - There’s our crotch measurement to get the perfect pants rise for your taste. Wear a pair of pants that fits you well, then measure from the highest point of the crotch seam to the base of the pants. Always remember to pull the fabric taught (not tight), to eliminate any sloppy measurements as a result of any slack in the fabric.

What About My Vest?

A 3-piece suit is designed with the vest in mind, so you should have the measurements you need. If you need measurements for the vest itself, put on the dress shirt and dress pants you intend to wear with it, then measure the waist just above the suit trousers, and repeat the chest (underarm) measurement in ‘jackets’ above.

Styling Tip - A vest is traditionally always worn with a jacket, unless you’re a snooker player. You’ll see it, oh yes, but don’t get caught up in this sartorial faux pas, unless your jacket is a stone's throw away. But also… this is fashion culture, not law, so be your own style boss and choose when you want to follow tradition, and when you want to break the ‘rules’.

Tips for Measuring Your Suit Correctly 

So are there any tricks involved in learning how to measure your suit size? Of course! Let’s take a look.

Sometimes, Just Try

Between brands, sizes can vary in a way that has nothing to do with anything at all. If you have the time, sometimes the best way to get the right size is to simply go to try on some suits in person and walk out with the one that looks best. No shame!

Even the fabric itself can affect how a suit fits, to a degree. If you’ve always worn heavy tweed suits, from Brand ABC, in size 40L, and you try their feather-light high-stretch line for the first time, you may find that the shoulders feel a little odd, or that the sleeves ride a little more than you’re used to. Working with fabric isn’t an exact science, and sometimes you’ll need to go with the flow and experiment with an open mind.

Getting Fitted?

If you’re being fitted in-store or ordering made-to-measure, you can do a few things to get the best results. Wear dress shoes and a dress shirt. Allow the staff to guide you since they know their own merchandise best. Don’t be afraid to bring along a picture to help communicate the fit you want, so everyone can be on the same page!

Be honest with your measurements - If you’ve gained a few pounds, let the tape measure ‘go there’. If you want a slim fit, don’t cheat by measuring too tightly. It’s super tempting to feel like you’re getting a step ahead, we get it, but trust the process, otherwise you’ll only end up cheating yourself and the fit will be compromised.

One Thing Is Not Like The Other

As we’ve already touched on, there are size variances between brands. Changing your style or fit preference might also affect how the suit feels on your body. Double-breasted suits feel tighter than two-piece suits because of the overlapping nature of the cut. Blazers are often fitted slightly looser than suit jackets. Slim fit or skinny-fit suits are meant to be very close-fitting. If you change the brand or style you’re looking for, you may need to adjust to a smaller or larger size. Don’t get too attached to the size on the label. Rather let the look and feel of the suit on your body speak for itself.

Don’t Be Literal

Your physical chest size probably won’t always match up to the size on the label, even with the user-friendly US system. A 38” chest and a size 38 aren’t necessarily the same, so always look at the size chart to help you translate your physical measurements into the correct size. Sometimes you can follow a size chart perfectly, and still achieve a less-than-ideal fit, this is just the nature of the beast with ready-made clothing.

Take a Stand

Be careful about your physicality when you’re measuring yourself, as this can have a negative effect on the measurements themselves. Don’t stand like you’re on parade. Don’t puff up your chest. Don’t place your arms rigidly at your sides or clench your thigh muscles. Take a “power” stance that feels natural without any stiffness, or slouching, like you’re standing waiting for a bus.

a man in a patterned suit


And there you have it! Suit sizes, explained. It can be difficult to match yourself up to a good suit if you don’t have a perfectly average body type, which few men do. Tailoring can help to tweak the fit, but a made-to-measure suit will always fit better and look more sophisticated than off-the-rack.

If you’re building a business casual wardrobe, need an attractive suit for a wedding or Mon-Fri suits for the office, investing in made-to-measure is the sure way to go. Store window promos may suck you into a good ready-made bargain, but it can be a false economy by the time you’ve forked out for necessary alterations to get the fit right.

On the other hand, life happens. You may receive a saddening invitation to a funeral, and realize suddenly that you don’t own a black suit and that your only option will be to run down to the local mall.

A well-chosen off-the-rack suit can be great if you know how to make the right choice, you have a relatively standard body type, and an element of good fortune is on your side on the day. Knowing how to measure men’s suits is a skill that will always serve you well, so go out there and find your match!

While you’re in the zone, why not schedule a consultation with your local tailor to improve your existing suits? A great fit is so worth it, we promise.