How To Read Men's Dress Shirt Sizes
By OTAA
Navigating men's dress shirt sizes can be confusing. Still, it's essential for a polished look, whether for a job interview, formal event, or wardrobe update. This guide will help you understand sizing and confidently choose the perfect shirt. Knowing how to read men's dress shirt sizes ensures you pair your shirts seamlessly with accessories like bow ties and tailored suits.
Start with our Size Finder, or compare Slim Fit vs Classic Fit when your collar fits but the body does not.
Already have a shirt to try? Run our seven-point dress shirt fit checklist to decide whether to change the collar size, cut or tailoring.
How Men's Dress Shirt Sizes Work
Men's dress shirt sizes can seem complicated, but they generally follow two central systems: numerical sizing and alpha sizing. Knowing how to measure and size, dress shirts is essential to find the perfect fit. Here's a breakdown to help you navigate these systems effectively.
Numerical Sizing Explained
On OTAA dress shirts, the collar measurement is the starting point. A label such as 40 (M) / 15.7 (M) displays the collar in centimetres, its labelled inch equivalent and the letter size. It does not give you the finished chest, waist or sleeve measurements. Check those separately in the shirt’s size chart.
Alpha Sizing Explained
Letter sizes such as Small (S), Medium (M) and Large (L) are brand labels. They do not guarantee the same measurements across retailers or cuts. At OTAA, use the collar value alongside the letter, then compare the finished garment measurements.
| Letter | Collar label (cm) | Inch label shown |
|---|---|---|
| S | 38 | 15 |
| M | 40 | 15.7 |
| L | 42 | 16.5 |
| XL | 44 | 17.5 |
| XXL | 46 | 18 |
| XXXL | 48 | 19 |
These are OTAA’s displayed collar labels, not exact mathematical conversions or chest measurements. Some shirts offer intermediate collars: check the available options on the individual product page. Slim Fit and Classic Fit can share a collar label while differing through the shoulders, chest and waist.
Critical Measurements for Men's Dress Shirts
Understanding key measurements is essential for finding the right fit. Here's how to measure yourself accurately for a men's dress shirt, including wrinkle-free options for a polished, low-maintenance look.
Neck Size
Wrap a flexible tape around the base of your neck where the collar sits, leaving room for one finger laid flat. Keep it comfortable rather than pressing into your skin. When you try the shirt, button the collar and check that you can turn your head and swallow comfortably.
Sleeve Length
For a body sleeve measurement, start at the centre back of the base of your neck, continue over your shoulder and down to your wrist bone, with your arm slightly bent. Follow the chart’s stated measuring points when comparing a finished shirt: body and garment sleeve measurements may use different starting points. A sleeve number is a length reference, not a promise that the sleeve is adjustable.
Chest Measurement
Measure around the widest part of your chest, under your armpits and across your shoulder blades. Keep the tape measure parallel to the ground. This measurement helps ensure a comfortable fit across your torso.
Shirt Length
Shirt length is crucial for a neat appearance, especially when tucked in. Measure from the base of your neck down your back to your desired length. The ideal length should cover your seat and hit mid-crotch, ensuring the shirt stays tucked in when you move or sit.
Waist Measurement
Measure around your natural waist, using the navel area as a practical starting reference. Keep the tape level, snug and comfortable, without drawing in your stomach. Use the same point each time and compare it only with a chart that uses the same measuring method.
Dress Shirt Fit Types Based on Build
Slim Fit
Slim Fit follows the body more closely, with a tapered waist and a trimmer sleeve shape. Choose it when the garment measurements give you the outline you prefer and enough room to move, rather than choosing by a body-type label.
Classic/Regular Fit
OTAA Classic Fit offers more ease through the shoulders, chest, waist and arms. “Regular” can mean something different at another brand, so compare finished measurements. If your collar fits but Slim Fit pulls at the stomach, try Classic Fit in the same collar size first.
How to Measure Yourself for a Dress Shirt
Measuring the Neck
Wrap a flexible tape around the base of your neck where the collar sits, leaving room for one finger laid flat. Keep it comfortable rather than pressing into your skin. When you try the shirt, button the collar and check that you can turn your head and swallow comfortably.
Measuring the Sleeves
For a body sleeve measurement, start at the centre back of the base of your neck, continue over your shoulder and down to your wrist bone, with your arm slightly bent. Follow the chart’s stated measuring points when comparing a finished shirt: body and garment sleeve measurements may use different starting points. A sleeve number is a length reference, not a promise that the sleeve is adjustable.
Measuring the Chest
Wrap the tape measure around the widest part of your chest, keeping it level and parallel to the floor. Measure the fullest part without pulling too tight.
Measuring the Waist
Measure around your natural waist, using the navel area as a practical starting reference. Keep the tape level, snug and comfortable, without drawing in your stomach. Use the same point each time and compare it only with a chart that uses the same measuring method.
Common Dress Shirt Size Conversions For Men
Understanding size conversions is essential when shopping across different sizing systems or regions.
US to European Sizing
Centimetres and inches are units, not different body types. Fifteen inches equals 38.1 cm; 39 cm is about 15.4 inches. OTAA’s common 38 cm collar is labelled 15 inches. Use the product’s actual label and size chart rather than assuming a European size always runs smaller.
Casual Shirt to Dress Shirt Sizing
A Medium in a casual shirt does not automatically identify your dress-shirt size. Start with a comfortable collar measurement, choose the cut, and compare chest, waist, shoulder and sleeve measurements with a shirt you wear well.
Frequently Asked Questions
How do I determine my OTAA dress-shirt size?
Start with your collar measurement, then compare the finished garment measurements and available fit on the product page. The Size Finder can help you choose.
What is the difference between numerical and letter sizing?
Collar numbers give a measurement reference; letters such as S, M and L are brand labels. At OTAA, read them together. Neither tells you the whole shirt’s dimensions.
Which measurements should I check?
Check collar, shoulders, chest, waist, sleeve length and body length, using each chart’s measuring points. Leave enough room to sit, breathe and reach.
Which fits does OTAA offer?
Our principal dress-shirt cuts are Slim Fit and Classic Fit. Compare the finished measurements in our Slim Fit vs Classic Fit guide.
Does a 15-inch collar equal 39 cm?
No. Fifteen inches equals 38.1 cm; OTAA’s common 38 cm collar is labelled 15 inches. Thirty-nine centimetres is about 15.4 inches. Labels may be rounded, so read the product’s chart.
Should I size up if the body feels tight?
If the collar is comfortable, compare the other cut first. Change collar size when the collar itself or the complete fit requires it.
