A shirt that looks excellent but grips at the neck makes an entire day unpleasant. A collar that is too loose looks careless and leaves the shirt looking unfinished, particularly with a tie. Yet plenty of men buy shirts on an estimated size or on feel, having never measured their neck.

That is an easily solved problem. Measuring your collar size takes under two minutes and needs nothing more than a soft tape measure. The result is a concrete number you can use against any brand's size chart.

This guide explains what collar size is, how to measure it correctly, what the average values are, how to check a shirt you already own, and how to convert between centimetres and inches.

What is collar size?

Collar size is the finished neck measurement of a shirt collar, expressed in centimetres. It is your own neck circumference plus a small amount of ease, measured at the height where a shirt collar naturally sits, and it determines how comfortably the shirt closes at the neck.

"Collar size is the most overlooked measurement when buying shirts. Men know their general size and buy on that basis, but general size says nothing about neck circumference. That varies from person to person regardless of shoulder or chest measurement. Always measure first."

Rick Ros, founder of Neycko Menswear

Collar size appears on shirts as a number between roughly 37 and 45 in European sizing. Most European brands use centimetres. British and American brands use inches, where a 39 centimetre collar corresponds to about 15.5 inches.

The ease matters. A collar cut to exactly your neck measurement would close against the skin with no room at all. Standard practice builds in roughly 1 to 1.5 centimetres, which is why the finger test below is part of the measuring method rather than an optional extra.

How do you measure your collar size step by step?

You can measure your collar size at home in four steps with a soft tape measure. The whole process takes under two minutes and needs no help from anyone else.

Step 1: use the right tool

Use a soft tailor's tape measure, not a rigid ruler. A soft tape follows the curve of the neck and gives an accurate reading. If you do not have one, wrap a piece of string around your neck, mark the overlap and hold the string against a ruler afterwards.

Step 2: set your posture

Stand upright in a relaxed posture. Lift your chin slightly without forcing the position. Breathe out normally before taking the reading, since holding a breath changes the measurement by several millimetres.

Step 3: measure around the base of the neck

Lay the tape horizontally around the base of your neck, just above the collarbones. That is where a shirt collar rests. Keep the tape level all the way around, without letting it ride up at the back.

Step 4: check the ease and read the number

Make sure exactly one finger fits comfortably between the tape and your neck. That is the standard allowance for a well-fitting collar. If there is more room than one finger, tighten the tape slightly. If it presses against the skin, loosen it. Read the measurement in centimetres and round up to the nearest half centimetre.

Collar size chart: neck measurement to shirt size

The table below shows the relationship between neck measurement and collar size, with approximate inch equivalents for British and American brands.

Collar size (cm)	Neck measurement (cm)	Inch equivalent	Availability
37	35.5 to 36.5	approx. 14.5	Limited
38	36.5 to 37.5	approx. 15	Common
39	37.5 to 38.5	approx. 15.5	Very common
40	38.5 to 39.5	approx. 15.75	Very common
41	39.5 to 40.5	approx. 16	Very common
42	40.5 to 41.5	approx. 16.5	Common
43	41.5 to 42.5	approx. 17	Common
44	42.5 to 43.5	approx. 17.5	Limited

The most commonly stocked collar sizes for men in the Netherlands and Belgium sit between 39 and 41 centimetres. Men outside that range benefit from checking availability before settling on a brand, since stock thins noticeably at both ends.

Which size do you choose if you fall between two?

If you fall between two collar sizes, always take the larger one. A slightly looser collar is more comfortable than a tight one and still looks neat with the top button closed. A collar that is too small cannot be corrected.

A tight collar is uncomfortable, restricts breathing and leaves visible pressure marks on the skin around the neck. That is noticeable to other people and unpleasant for you, particularly across a long working day or a formal event. A slightly roomier collar disappears under a tie or simply goes unnoticed when the rest of the shirt fits well.

If you wear ties regularly, take the larger size without hesitation. A tie pulls the collar closed and makes the difference between comfortable and constricting considerably sharper.

Does collar size depend on the fit of the shirt?

No. Collar size is a fixed body measurement and does not change with the fit you choose. A slim fit shirt and a regular fit shirt in the same collar size have an identical collar.

The difference between fits sits in the body, the shoulders and the waist, not in the neck. That means your collar size stays the same regardless of which cut you buy, which makes it the single most portable number in your measurements.

What does vary is how brands interpret their own sizing. Some produce collars that run slightly small or large against the label. Always measure yourself and compare against the specific size chart of the brand you are buying. Our explainer on what slim fit means covers the body fits, and our broader guide to determining your clothing size covers the rest of the measurements.

How do you check the collar size of a shirt you already own?

Lay the shirt flat with the collar unbuttoned and straightened. Measure along the collar band from the centre of the button to the far edge of the buttonhole. That distance in centimetres is the collar size, with no further calculation needed.

A shirt measuring 40 centimetres from button centre to buttonhole is a size 40 collar. There is no doubling and no subtraction involved: the figure you measure is the finished collar size as the manufacturer labels it.

This is the fastest method if you already own a shirt that fits well at the neck. Measure that collar, note the number, and use it as your reference when buying. It also works as a cross-check against your body measurement, since the two should land within about a centimetre of each other.

When does your collar size change?

Collar size changes with significant weight gain or loss, and with muscle development in the neck and upper back. Re-measure if your body has changed noticeably or if you have not bought shirts in a while.

Men who train regularly, particularly with heavy pressing and pulling movements, often find their collar size increases even when total body weight stays the same. That is a specific situation where re-measuring pays off immediately, because the shirts that fit two years ago will now grip.

A practical habit: re-measure every two years, or before any shopping trip where shirts are on the list.

How do you convert collar size between centimetres and inches?

Divide your collar size in centimetres by 2.54 to get the inch equivalent. European brands label in centimetres, while British and American brands label in inches, so the conversion comes up constantly when buying online.

Worked examples:

• 39 cm divided by 2.54 equals 15.35 inches, sold as 15.5.
• 41 cm divided by 2.54 equals 16.14 inches, sold as 16.
• 43 cm divided by 2.54 equals 16.93 inches, sold as 17.

Round up when the result falls between two available sizes. A slightly roomier collar is always the safer error.

Which other measurements matter when buying a shirt?

Collar size determines the neck fit, but a well-fitting shirt also needs the right chest, shoulder width and sleeve length. Four measurements cover a shirt purchase completely.

• Collar size determines the neck.
• Chest circumference determines the body size in combination with the fit.
• Shoulder width determines whether the shoulder seam lands correctly on the end of your shoulder.
• Sleeve length is measured from the shoulder point along the outside of the arm to the wrist bone.

Shoulder width is the one unfixable fit problem: correcting it means rebuilding the garment, which is rarely worth the cost. Every other measurement can be adjusted by a tailor. The buying priority follows from that: check the shoulder first, then the collar, then everything else.

For collar shape rather than size, our guide to the different shirt collar types covers which shapes suit which face and jacket, and what to wear under a shirt covers the layer beneath. If your shirt works loose during the day, see keeping your shirt neatly tucked in.

Frequently asked questions

How do I measure my collar size at home?

Wrap a soft tape measure horizontally around the base of your neck, just above the collarbones. Make sure exactly one finger fits comfortably between the tape and your neck. Breathe out normally before reading. Note the measurement in centimetres and round up to the nearest half centimetre. That is your collar size.

What is the average collar size for men?

The most commonly stocked collar sizes sit between 39 and 41 centimetres, corresponding to a neck measurement of roughly 37.5 to 40.5 centimetres. That range also has the widest availability across brands. Men outside it should check stock before committing to a brand, since sizes thin out at both ends.

What should I do if my collar size falls between two sizes?

Always take the larger size. A slightly roomier collar is more comfortable than a tight one and still looks neat with the top button closed. If you wear ties regularly the larger size matters more, because a tie pulls the collar closed and makes a tight collar uncomfortable across the day.

How do I convert my collar size from centimetres to inches?

Divide your collar size in centimetres by 2.54. A 39 cm collar becomes 15.35 inches, sold as 15.5. A 41 cm collar becomes 16.14 inches, sold as 16. A 43 cm collar becomes 16.93 inches, sold as 17. Round up when the result falls between two available sizes.

Does my collar size change if I lose or gain weight?

Yes. Neck circumference changes with significant weight change and with muscle development in the neck and upper back. Strength training can increase collar size without any change in total body weight. Re-measure before any shopping trip that includes shirts, or at minimum every two years.

Conclusion

Measuring your collar size is simple and takes under two minutes. Measure around the base of the neck just above the collarbones with a soft tape, allow one finger of ease, and read the number in centimetres. The most commonly stocked sizes fall between 39 and 41 centimetres. When in doubt, always take the larger size.

The practical takeaway: memorise the number. A collar size you can recall in a shop or at a checkout is worth far more than one you measured once and forgot, and it is the single fastest way to stop returning shirts that never had a chance of fitting.

Discover the Neycko collection

At Neycko, polos, t-shirts and trousers are made from Italian techno jersey with four-way stretch, which gives more room at the neck and shoulders than traditional woven fabrics. Browse the polo collection, the t-shirt deluxe collection and the newest models in the new-in collection. Read the full Dutch guide: boordmaat meten: zo bepaal je de juiste kraagmaat.