Men's Suit Size Chart: UK, US and EU Conversion Guide

Men's suit sizes are based on your chest measurement: in inches for UK and US sizing, in centimetres for European systems. A UK 40 jacket fits a 40-inch chest, and the same chest takes an EU 50 in Italian or French sizing. UK and US suit sizes are identical by number. This guide brings together the complete men's suit size chart, international conversions and step-by-step measuring instructions, drawing on what we've learned fitting customers at MrGuild's London atelier since 2018. Use the conversion table below to translate your size, then follow the measuring guide to confirm it before ordering from our suit collection.

Suit Size Conversion Chart: UK, US and EU

To convert a UK suit size to EU or Italian sizing, add 10 to the number. UK and US sizes are the same. That single rule covers most international suit shopping, and the table below maps it size by size against the chest measurement each one is cut for.

UK / US Size	EU / Italian Size	Chest (inches)	Chest (cm)
36	46	36	91
38	48	38	97
40	50	40	102
42	52	42	107
44	54	44	112
46	56	46	117
48	58	48	122

A UK 40 and a US 40 are the same labelled size. If you wear a 40 in New York, you wear a 40 in London. What changes between the two markets is the cut, not the number: British tailoring tends towards more structured shoulders and a trimmer armhole, so the same size can feel closer fitting.

EU and Italian sizing follows one consistent rule. Add 10 to your UK or US number and you have your continental size, whether the label is Italian, French, German or Spanish. A UK 42 becomes an EU 52, designed for the same 42-inch chest.

Letter sizes are the least reliable system of the three. An L in one brand is an XL in another, so treat letters as a shortcut rather than a measurement. MrGuild lists a letter equivalent against every numbered size, with a UK 40 sitting at L, but the numbered size is the one to buy from whenever you have the choice.

How Suit Sizes Work: Numbers and Letters Explained

A suit label such as 38R combines two pieces of information. The number is the chest size in inches under UK and US sizing, and the letter is the jacket length: S for short, R for regular, L for long. So a 38R is a jacket cut for a 38-inch chest in regular length.

The length letter is driven by your height, not your chest. As a working guide:

• XS: under 5'7" (170 cm)
• S: 5'7" to 5'9" (170 to 175 cm)
• R: 5'9" to 6'0" (175 to 183 cm)
• L: 6'0" to 6'3" (183 to 191 cm)
• XL: over 6'3" (191 cm)

Most high street ranges stop at S, R and L. MrGuild cuts all five lengths, including XS and XL, because torso length is where off-the-rack sizing fails tall and shorter men first.

Treat the height bands as a starting point rather than a rule. The same height can be carried in different ways, long in the leg or long in the torso, and it's the torso that decides the jacket length you need.

How to Measure Yourself for a Suit

To measure yourself for a suit, you need five measurements: chest, waist, shoulder width, sleeve length and jacket length. All you need is a soft tape measure, a mirror and about ten minutes. Wear a thin shirt, stand naturally and keep the tape level but never pulled tight.

A second pair of hands helps, particularly for the shoulder and sleeve measurements, but every step below can be done alone in front of a mirror. Record each figure in both inches and centimetres so you can read any brand's chart without converting later.

Chest Measurement

Wrap the tape around the fullest part of your chest, under the armpits and across the shoulder blades. Keep it parallel to the floor all the way round.

The most common mistake here is puffing the chest out or holding a deep breath. Breathe normally. An inflated chest reading puts you a full size out, and chest is the measurement your jacket size is built on.

Waist Measurement

Measure at your natural waistline, above the navel and below the ribcage. This is higher than where most men wear their trousers.

Don't measure at the trouser line. Suit trousers sit at the natural waist, and a reading taken at the hips will mislead both your trouser size and your drop, which we cover further down.

Shoulder Width

Run the tape across your upper back, from the outer edge of one shoulder to the outer edge of the other. This one genuinely is easier with help.

Shoulder width matters more than any other figure on this list, because shoulders are the hardest and most expensive part of a jacket to alter. Measure point to point across the shoulder bones, not around the curve of the neck.

Sleeve Length

With your arm slightly bent, measure from the shoulder seam down to the base of the thumb.

Keep that slight bend. A fully straightened arm shortens the reading, and the result is a sleeve that rides up the moment you move. Done correctly, the jacket sleeve should finish at the wrist bone and show around half an inch of shirt cuff.

Jacket Length

Measure from the base of the collar to where you want the hem to sit, typically just covering the seat.

Jacket length is sold in standard bands rather than exact figures: Short (S), Regular (R) and Long (L). Don't assume Regular covers everyone of average height; check your reading against the height bands in the label section above.

What Is the Drop in Suit Sizing?

The drop is the difference between your chest and waist measurements, and it shapes how a jacket is cut more than the chest size alone. A 42-inch chest with a 36-inch waist and a 42-inch chest with a 38-inch waist wear the same size on the label but not the same suit.

Off-the-rack suits are built around a standard drop of 6 inches: a size 40 jacket assumes a 34-inch waist. From there:

• Standard drop, 6 inches: proportional build, the default cut for most ready-to-wear suits
• Athletic drop, 7 to 8 inches: broad chest tapering to a narrower waist
• Classic or fuller drop, 4 to 5 inches: chest and waist measurements sitting closer together

If your own drop is far from 6 inches, the answer isn't a different size; it's the same size with the waist tailored to close the gap. We come back to which builds suit which drop in the body type section below.

Slim Fit vs Regular Fit vs Tailored Fit: What the Labels Mean

Slim fit follows the line of the body, with a suppressed waist and narrower sleeves and trousers. Regular fit, sometimes labelled classic fit, gives a straighter cut with more room through the chest, waist and thigh. Tailored fit sits between the two: shaped, but less closely than slim.

These labels describe the cut, not the size. A 40 slim and a 40 regular are built for the same chest; what differs is how much cloth sits around it. That's why switching fit shouldn't mean switching number.

The catch is that no two brands draw these lines in the same place. One label's tailored fit is another's slim, so the fit name tells you the direction of the cut, never the exact shape. We keep it simple by cutting one fit and doing it properly: slim, with the proportions decided in our atelier rather than by a label convention.

How to Choose a Suit Size for Your Body Type

Your drop and the cut you choose together decide how a suit sits on your build. The three profiles below cover most men; find yours, note the drop range it pairs with, and you'll know what to expect off the rack.

Athletic Build

Broad chest, defined waist, a drop of 7 to 8 inches. Buy for the chest and shoulders, since neither can be altered, and expect the waist to need suppression. Off the rack, watch for pulling across the chest when the jacket is buttoned; if it pulls, go up a size and tailor down.

Standard Build

Proportional chest and waist, around the 6-inch drop that ready-to-wear sizing is built on. Most off-the-rack suits will fit you well with minor alterations at most, typically a trouser hem or a touch off the sleeves. Your size chart number is usually your answer.

Fuller Build

Chest and waist within a few inches of each other, a drop of 4 to 5 inches. A straighter, classic cut works with your proportions rather than against them. A slim cut, including ours, only works here with tailoring through the waist and sides, so budget for that adjustment or choose the larger size and shape it down.

How Suit Trouser Sizes Work

Suit trousers are sized by two numbers in the UK: waist and inside leg, both in inches. When a suit is sold as a set, the trousers usually come with a fixed 6-inch drop from the jacket number, so a size 40 jacket pairs with 34-inch-waist trousers, a 42 with a 36.

This is the retail cousin of the drop covered earlier. The set pairing assumes the standard build; if your own chest-to-waist difference is larger or smaller, the trouser waist is the part that gives. Most suit trousers carry enough cloth in the waistband for a tailor to take it in or let it out by an inch or two, which is why buying on jacket size still works for most men.

Inside leg runs from the crotch seam to where the hem meets your shoe, measured without shoes on. Suit trousers typically come in one standard leg length with allowance for hemming: ours are cut to an 82 cm inside leg, around 32 inches, across every size, with the hem finished to your height from there. Treat the waist as the number to get right and the hem as routine tailoring.

Our trousers are sized from 30 to 42, and the measurements behind every size, waist, thigh, rise and leg opening, are published in our size reference rather than left to the label. The three trouser fits are covered in the next section.

MrGuild Sizing: How Our Suits Are Cut

Every suit we make is slim fit by design: tapered through the waist, higher in the armhole, and finished with the peak lapel that has become the MrGuild signature. We cut chest sizes 36 to 48 in the five jacket lengths covered above, XS through XL, working in the London tailoring tradition since 2018.

Our labels follow UK numbered sizing, and the complete size reference lists the EU, international letter and Chinese equivalents against every size, so you can cross-check whichever system you know your measurements in.

Trousers come in three fits: standard, slim and slimmer. The jacket size stays the same across all three; only the trouser line changes.

Two notes for specific styles. Our double-breasted suits use the same numbered sizing but wear closer through the chest, because the overlapping front adds a layer of cloth across the body. And in our three-piece suits, the waistcoat is sized to match the jacket, so there is no third measurement to take.

Common Sizing Questions

Should I Round Up or Down When Between Suit Sizes?

Round up. A slightly larger jacket can be taken in at the waist, sides and sleeves, and the result looks made for you. A too-small jacket has nowhere to go: most seams hold around half an inch of spare cloth, and the shoulders cannot be expanded at all.

There's a comfort case too. A jacket that closes with strain across the chest will pull every time you sit, reach or drive. The bigger size, shaped down by a tailor, moves with you instead.

Can I Wear a US Suit Size in the UK?

Yes. UK and US suit sizes match by number, so a US 42 is a UK 42 with no conversion needed. The difference you may notice is in the tailoring itself. British jackets are often built with firmer shoulders and sit higher under the arm, so the same number can feel trimmer than it does at home. The label transfers; the silhouette doesn't quite.

How Do Suit Sizes Vary Between Brands?

The number should mean the same chest everywhere, but each brand decides how much room to cut around it. That is how a 40 in one shop ends up wearing like a 38 or a 42 in another. Trust garment measurements over labels whenever a brand publishes them.

Our own sizing follows standard UK conventions. If you wear a 40 at most British retailers, you wear a 40 with us; the difference you'll notice is the slim cut through the waist, not the number on the label.

Can You Estimate Your Suit Size from Height and Weight?

Roughly, yes. Height-and-weight tables land most men within one size of their true fit, and 40R is generally cited as the most common men's suit size sold. Use the estimate to shortlist, never to order. Two men of identical height and weight can sit two sizes apart, because it's the chest measurement that decides.

When to Get a Suit Tailored

Off the rack plus one round of alterations is the normal route to a properly fitting suit, not a sign the sizing failed. The three most common adjustments are the trouser hem, the sleeve length and suppression through the jacket waist, all quick work for a competent tailor.

The limit is around 2 inches. A tailor can take a jacket in by about that much before the pockets, button stance and balance start to distort. If your fitting needs more than 2 inches of adjustment, the answer is a different size, not more pinning.

Frequently Asked Questions

What size suit should I get based on my chest measurement?

Your suit size in UK or US sizing matches your chest measurement in inches, so a 40-inch chest typically wears a size 40 jacket. For EU or Italian sizing, add 10 to the UK/US number: a UK 40 becomes an EU 50. Always check the brand's own chart, as cuts vary between makers.

What does 38R mean in suit sizing?

38R is a jacket cut for a 38-inch chest in regular length. The number is the chest measurement in inches under UK and US sizing; the letter is the jacket length, with S for short, R for regular and L for long. We also cut XS and XL lengths for shorter and taller men.

How do I convert UK suit sizes to EU sizes?

Add 10 to the UK number. A UK 40 is an EU 50, a UK 42 an EU 52, and the same rule holds for Italian, French, German and most other European systems. The two labels describe the same chest measurement; only the numbering convention differs.

Should I round up or down if I'm between suit sizes?

Round up. It is far easier and cheaper to alter a slightly larger suit down at the waist, sides or sleeves than to make a smaller suit fit a bigger frame. Shoulders cannot be expanded after the fact, and they are the most critical fit point on any jacket.

How should a suit jacket fit at the shoulders?

The seam should sit flat at the outer edge of your natural shoulder, neither hanging past it nor cutting inside it, with no pulling or rippling across the upper back. Shoulder fit comes first because once a jacket is made, the shoulders are close to impossible to re-cut.

[Editör notu] TODO (Hafta 8): Cluster 4.6 yayınlandığında yukarıdaki omuz cevabından "how a suit jacket should fit" anchor'ı ile link verilecek.

You now have the number, the conversion and the measurements to back it up. The rest is choosing the suit. Browse our suit collection with your size confirmed, and if you're dressing a wedding party, our size box for groomsmen takes the guesswork out of fitting the whole group at once.