Dress Shirt Sizes Explained: Collar, Sleeve and Fit

Dress shirts are sized by two numbers: the collar size, which is your neck circumference, and the sleeve length. In US and UK sizing, both are given in inches, so a shirt labeled 16 34/35 has a 16-inch collar and fits sleeve lengths of 34 to 35 inches, measured from the center back of the neck to the wrist. Most European brands give the collar in centimeters (a 16-inch collar is about EU 40/41) and offer the sleeve as standard or extra long. Measure your neck and sleeve once, then choose a cut such as slim or regular to match your build.

This guide explains the numbers, shows how to measure yourself and lists what to check in the mirror. To convert a collar size between inches and centimeters, use the clothing size converter and choose "Men: shirt collars".

What the numbers on a shirt label mean

A typical dress shirt label carries up to four pieces of information:

Label part	Example	Meaning
Collar size	15.5 or 39	Neck circumference in inches (US/UK) or centimeters (EU)
Sleeve length	34 or 34/35	Sleeve in inches, from center back of the neck to the wrist
Fit	Slim, regular, classic	How much room the body of the shirt has
Letter size	M, L	A rough range, common on casual shirts

Ready-to-wear shirts often group sleeves into pairs such as 32/33, 34/35 and 36/37 to keep the number of sizes manageable. Some brands sell exact sleeve lengths instead. Casual shirts often skip both numbers and use letter sizes only.

Collar size: the number that matters most

The collar is the least forgiving part of a dress shirt. A collar that is too tight is uncomfortable as soon as you button it; one that is too loose looks sloppy under a tie. Sleeves can be shortened by a tailor; a collar cannot really be enlarged.

How to measure your neck

1. Stand straight and look ahead.
2. Wrap a soft tape measure around the base of your neck, where a shirt collar sits, just below the Adam's apple.
3. Slide one finger under the tape so it is snug but not tight.
4. Read the number and round up to the next half inch or full centimeter.

More detail on measuring, including chest and waist, is in our guide on how to measure yourself for clothes.

Measure a shirt that fits instead

If you have a shirt whose collar fits well, lay the open collar flat and measure from the center of the top button to the far end of the buttonhole. That distance is the collar size. It is a good cross-check for your body measurement.

Collar size conversion

These are common reference values. Brands can differ by half a size, so always check their chart.

US/UK (inches)	EU (cm)	Letter
14	36	S
14.5	37	S
15	38	M
15.5	39	M
16	40/41	L
16.5	42	L
17	43	XL
17.5	44	XL
18	45	XXL

Italian shirtmakers use the same centimeter scale; our guide to Italian clothing sizes covers the rest of the Italian system.

Sleeve length: why the number is longer than your arm

The sleeve number on a US or UK shirt surprises many people: 34 or 35 inches seems far too long for an arm. That is because it is measured from the center back of the neck, over the shoulder and down to the wrist, not from the shoulder seam.

How to measure your sleeve length

1. Stand with your arm relaxed and slightly bent at your side.
2. Ask someone to place the tape at the center back of your neck, at the bone you can feel where the neck meets the back.
3. Run the tape across the top of the shoulder, down the outside of the arm, over the elbow, to the wrist bone.
4. Read the number in inches or centimeters and round up to the nearest half inch.

How European brands give sleeve length

Many European brands sell one standard sleeve per collar size and a separate extra-long version, sometimes also a shorter one. Others state the sleeve in centimeters. Conventions differ: some brands measure from the center back, others from the shoulder seam, and the two numbers can be several centimeters apart. Check how the brand measures before comparing.

Fit: slim, regular and classic

Collar and sleeve tell you the size; the fit tells you the shape of the body. Names vary by brand, but most follow a similar range:

Fit	Body	Who it tends to suit
Slim / extra slim	Close through chest and waist, often darted at the back	Slender builds, wearing under a fitted jacket
Tailored / modern	Gently shaped, some room in the chest	Most average builds
Regular / classic	Straight and roomy	Broader chests and stomachs, more movement

If you fall between two fits, the shirt that shows no pulling at the buttons and no large folds at the waist is the right one. A tailor can take in the sides of a shirt that is too roomy; a shirt that pulls cannot be let out.

How a dress shirt should fit: a mirror checklist

Put the shirt on, button it fully including the collar, and check:

• Collar: one finger, at most two, fits between collar and neck.
• Shoulders: the shoulder seam ends at the edge of your shoulder bone, not on the upper arm.
• Chest: no pulling into an X-shape around the buttons when you stand or sit.
• Waist: no balloon of fabric above the trousers; small folds are fine in a regular fit.
• Sleeves: the cuff reaches the base of the thumb with arms relaxed and stays at the wrist when you bend your elbow.
• Cuffs: snug enough not to slide down over your hand; a watch cuff may be a little wider.
• Length: the shirt stays tucked when you raise your arms.

Under a jacket, about 1 to 1.5 cm of cuff should show below the jacket sleeve. Our guide on how a suit should fit explains the jacket side of that balance.

Worked example: finding a size abroad

Here is a hypothetical case to show the method.

Daniel measures his neck at 38.6 cm with one finger under the tape and his sleeve at 86 cm from the center back of the neck.

1. Collar: 38.6 cm rounds up to EU 39. In the reference chart, EU 39 equals US/UK 15.5.
2. Sleeve: 86 ÷ 2.54 = 33.9 inches, which rounds to 34. A US shirt labeled 15.5 34/35 fits.
3. European brand: he picks collar 39 with the standard sleeve, then checks the brand's table to confirm that the standard sleeve measured from the center back is close to his 86 cm.
4. Fit: with a slim build, he tries the tailored fit first and keeps the slim fit for wearing under a suit.

The clothing size converter does step 1 instantly. For other garments, our overview of international clothing size conversion has the women's and suit charts.

Shrinkage and fabric

Cotton can shrink slightly, especially in the first washes and in a hot tumble dryer. Some brands cut their shirts with this in mind; others pre-treat the fabric. If a collar fits exactly when new and the care label allows a hot wash, expect it to feel a little closer after washing. Washing at lower temperatures and drying on a hanger reduces shrinkage and creasing.

Fabric also changes how a size feels. A shirt with a little stretch is more forgiving in a slim fit; a crisp poplin or twill will show every tight spot.

Common mistakes

Choosing by letter size alone. M or L tells you little about collar and sleeve. For dress shirts, use the numbers.

Measuring the sleeve from the shoulder. On US and UK labels, the sleeve starts at the center back of the neck. A shoulder-to-wrist measurement leads to sleeves that are far too short.

Buying a tight collar to get a slimmer body. Choose the collar that fits and pick a slimmer cut instead.

Ignoring the cuff. A cuff that slides down to the knuckles makes even the right sleeve length look too long.

Forgetting the tie test. If you wear ties, close the top button in the fitting room. A collar that only works open is not a dress shirt collar for you.

Quick checklist before ordering

• Neck measured with one finger under the tape, rounded up
• Sleeve measured from the center back of the neck to the wrist
• Collar converted to the brand's system (inches or centimeters)
• Brand's chart checked for how it measures sleeves
• Fit chosen for your build: slim, tailored or regular
• Care label checked for washing temperature and drying

Two measurements and one fit decision are all a dress shirt needs. Write them down once, check them against each brand's chart, and buying shirts online becomes as easy as buying them in a shop.