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How to Measure for Blazer Size

When you want to look smart but not too formal, you often choose a blazer rather than a full two-piece suit. Versatile blazers can mix and match many outfits, from nice jeans and loafers to pencil skirts and heels. But wearing the perfect business casual blazer outfit depends on knowing how to measure for blazer size.

Key measurements to determine blazer size include the chest circumference and length. Sleeve length, shoulder width, and waist measurements can also help pinpoint the correct blazer size. It is important to take blazer measurements over clothing because this garment fits more loosely than a suit jacket.

In this article, you will discover how to measure yourself to find your blazer size. You will learn how to use blazer sizes for men and for women. Finally, you will discover the difference between a blazer and a suit jacket fit.

How to Measure for Blazer Size

How Do Blazer Sizes Work?

Blazer sizes for men list a number followed by a letter, like 40R, and blazer sizes for women typically use the US sizing system of even numbers starting at zero.

The number listed as the first part of men’s blazer sizes describes your chest measurement. The letter refers to the length of the jacket, typically either S for short, R for regular, or L for long.

This simple system makes it easy to find the right size for you, as the most important step is to take an accurate chest measurement. Suit jackets and sports coats for men also use this sizing system.

That said, the chest measurement portion of the size means that the blazer is designed to fit someone with a chest of that circumference. It does not mean that the garment itself has that measurement across the chest because a blazer should fit more loosely over your clothing than a suit jacket–it should never hug your chest too closely!

A blazer looks a bit like a suit jacket but has an overall more casual cut. It will look a bit boxier and you can wear it over a sweater or vest instead of just over a dress shirt. Plus, blazers usually feature solid-colored fabric.

Blazer sizes for women use a deceptively simple-looking even-numbered sizing system that can include many variations. This happens for two reasons.

First, women’s blazers come in more cuts and styles than men’s blazers. For instance, you might find a blazer with a ruffled peplum tail for women or a mandarin collar instead of the traditional lapels. These variations in style can have many different intended fits, some looser and some tighter than others.

Second, women’s sizing does not use standardized measurements, so a size 2 from one brand can have different measurements than a size 2 from another brand! This makes taking accurate measurements before buying a women’s blazer super important.

How to Measure for Blazer Size

The most important measurement to determine blazer size is the chest circumference for both men and women. Other key measurements for the perfect fit include the waist, hips/seat, and sleeve length.

If you plan to wear your blazer on top of a thick shirt or a sweater, take the measurements while wearing those clothes.


How To Measure Chest Size

The most essential measurement you need to take to find the right blazer size for you is the chest measurement. For men, this measurement will serve as the size. For example, if you have a 36” chest measurement, you will want a size 36 blazer!

  1. Position yourself in front of a mirror and find a flexible tape measure.
  2. Locate the fullest part of your chest. For men, this usually means right below the armpits. For women, begin at the widest portion of your bust.
  3. Wrap the tape levelly around your torso at this point. Use the mirror to help make sure you keep the tape straight all the way around.
  4. Pull the tape snug but not too tight–you do not want to see it indenting into your clothes.
  5. Place two fingers beneath the tape.
  6. Write down the number where the ends of the tape meet up.


Another crucial measurement for blazer fit is the length of the jacket.

Men’s blazers typically come in pretty standard short, regular, or long lengths. While the precise measurement of a short or long blazer can vary a bit from brand to brand, generally, short lengths work best for men below the height of 5’8”, regular-length blazers work well for men between 5’8” and 6’2”, and anyone over the height of 6’2” should wear a long jacket.

Men’s and women’s blazers should almost always comfortably cover at least the top half of the seat, though, so you do want to take a length measurement to ensure that you don’t end up with an awkwardly too-short tail on your jacket!

  1. Get a friend to help or position yourself with a back to a mirror.
  2. Place the short end of a tape measure at the nape of your neck or the bottom edge of your shirt collar at the center of your neck.
  3. Keep holding the tape at the base of your neck and use your other hand to flatten the tape at the small of your back.
  4. Keep holding the tape at the small of your back and let go of the tape at your neck to free up your hand.
  5. Using the mirror, decide where you want the hem of the blazer to end on your seat. Pinch the loose tape at that point.
  6. Write down the number at this point.


Measuring the waistMeasuring around your natural waist allows you to find a blazer that will comfortably button without gapping open at your chest or wrinkling too tightly across your midsection.

  1. To locate your natural waist, measure about one inch below your navel. You do not want to use your regular pant waist size because jeans or trousers often have waistbands that fall at other points on your torso, not at your real waistline.
  2. Wrap a flexible tape measure levelly around yourself at this point.
  3. Before you pull the tape snugly, place two fingers between your clothes and the tape.
  4. Snug the tape and write down the waist measurement.


Besides the chest measurement, the hip/seat measurement is the most important sizing factor you need to figure out for women’s blazers. For women, the hips often form the widest part of the torso. This makes getting an accurate measurement essential to a good fit.

For men’s blazers, this measurement is a good idea just because you want to make sure the tail of the jacket does not fit too snugly across your seat.

  1. Finding the fullest part of your hips and seat can take a little work. To do this, wear an old pair of close-fitting pants or leggings. Measure down the outer side seams of the pants on each leg and mark every inch between the top of your hip and the point where your hip noticeably curves back in toward your leg.
  2. Now wrap a tape measure levelly around your hips at each marking. Note down the measurements.
  3. Look at your list and find the biggest measurement. Double-check the measurement and this time, insert two fingers between your leg and the tape.
  4. Use this as your hip measurement!


Measuring Shoulder Width for Clothes

Getting the right shoulder fit in blazers matters a lot for both men and women because ill-fitting shoulder seams look obvious and make you appear poorly dressed. You want the seam where the sleeve of the blazer connects to it to fall right at the tip of your own shoulder rather than dragging up onto your shoulder or falling onto your arm.

To measure shoulder width:

  1. Put on a thick plaid shirt, well-fitting blazer, or suit jacket before you take this measurement. The seams in the garment will help you get the right distances.
  2. Ask a friend to help, if possible. You will find it tough to take the measurement on your own back!
  3. Have your friend place the short end of the tape where the sleeve connects to the shirt or jacket at the top of your shoulder.
  4. Now have them smooth the tape over the curve of your back right below your neck, across to the same shoulder seam point on your opposite shoulder.
  5. Right down that measurement.

Sleeve Length

Sleeve length measurement

Blazer sleeves should reach just about to the top of your wrist when you stand with your arms at your sides. This is because you want close to half an inch of the cuff of your shirt to show beneath the blazer sleeve. You never want blazer sleeves to hang down so far that they reach the heel of your hand because this makes it seem like your jacket is too big.

To measure for blazer sleeve length:

  1. Hold one end of the tape measure at the top of your shoulder, where you can see the seam that connects the sleeve to your shirt or jacket.
  2. Keeping your arm straight at your side, smooth the tape down the length of your arm. Stop right above your wrist.
  3. Write down that length.

On a Blazer

Blazer measurement

If you feel uneasy about taking accurate measurements of yourself, you can also measure a blazer that fits just the way you like. This is the technique used clothing sellers use to list sizes on eBay or other sites, too.

  1. For a chest measurement, spread the jacket face-down on a hard surface. Stretch a tape measure or ruler straight across the back of the jacket from side seam to side seam, right beneath the armpits.
  2. For jacket length, start with the jacket face-down and smoothed out. Then place one end of the tape at the center back of the neck, right below the collar. Smooth the tape straight down the back of the jacket to the hem.
  3. To get a shoulder width measurement, spread out the jacket with the back facing up, smoothed out with no wrinkles in it. Measure from one shoulder seam to the other across the upper back of the garment.
  4. For a waist measurement, spread the jacket face on a flat surface, once again smoothing out any wrinkles. Make sure the lapels lie flat and button the buttons. Measure straight across the waistline at the middle button for a three-button blazer or at the top button for a two-button style.
  5. Finally, to get the sleeve length, place one end of the tape measure at the top of the shoulder, where the sleeve connects to the jacket. Smooth the tape straight down the length of the sleeve to the hem.

Blazer Size vs Shirt Size

Men’s blazers and shirts use different sizing systems, while women’s blazers and shirts use the same sizing system. All blazers and jackets always contain larger measurements than shirts because they should fit more loosely on your body than a shirt.

Men’s shirt and blazer sizes look completely different. Men’s blazer sizes depend primarily on the chest and length measurements. This means that a 40L blazer will fit someone with a 40-inch chest measurement height of over 6’2”.

Men’s shirts, in contrast, use sizes based on sleeve length and neck circumference. Shirt sizes for men list two numbers, like 14 34 (or 14 34/35). The first number indicates the neck measurement of the collar, and the second number lists the sleeve length, often given in a range such as 34/35.

So you can’t just use your shirt size to buy a men’s blazer! Make sure you use the correct measurements for each sizing system.

Women’s shirts and blazers often do use the same even-numbered sizing system. This gets confusing because while you could buy a women’s blouse and a women’s blazer in size 2, the blazer would fit much more loosely than the blouse. This is because clothing brands design jackets with more space than shirts on purpose, so you can wear your jacket over a shirt, sweater, or turtleneck.

If you wear a size 4 in women’s shirts, you will usually also fit a size 4 in women’s blazers.

How to Measure Women’s Blazer Size

Measure Women Blazer Size

The three most important measurements for women’s blazer size are the chest, waist, and hips. You may also want to take the additional length and sleeve length measurements, but getting the chest, waist, and hips is crucial if you want a blazer to fit your particular body type. This is because these three measurements will give you the shape of the fullest and narrowest portions of your torso.

Once you have your three essential measurements, pull up the sizing chart offered by the clothing brand you like. Look for the column labeled “chest” first, and find your measurement in that column. Trace along the row to see if the waist and hip measurements for that size also match your measurements.

If any of the three measurements in that size do not match yours, the garment will not fit you properly. For example, suppose the chest and waist measurements in size 8 blazer perfectly match your measurements, but the hip measurement listed is two inches too small. This blazer will cling too tightly around your seat and look too small.

As a pro tip, ensure you take your measurements for the blazer while wearing the outfit you plan to pair with the jacket.

Blazer Sizes

Blazer Sizes

Now that you know how to measure yourself for a blazer check out some answers to common blazer sizes questions!

What Size is a Size 10 Blazer?

A Size 10 blazer is sized for women and typically has a 34” to 36” chest measurement with a 29” to 30” waist measurement. This sizing normally falls into the midrange for women’s blazers, meaning that you could also consider it a size medium.

What Size s a 34 Inch Blazer?

A 34-inch blazer is sized for men and the “34” means that the jacket has a 34-inch chest measurement. In most cases, men’s blazer sizes will also provide a length indicator such as S for Short, R for Regular, or L for long, following the numerical size.

What is a 42 Size Blazer?

A Size 42 blazer for men has a chest measurement of 42 inches and falls on the larger end of the off-the-rack blazer sizes for men. If you have a 42-inch chest circumference, this blazer will probably fit you!

Blazer Size Chart Women’s

Once you have your measurements noted down, you will need to compare them to a blazer size chart for women to match up your measurements with the appropriate size for you. Most clothing brands publish their sizing charts online for easy access.

But keep in mind that every clothing brand–and even every style of blazer within that brand–may use slightly different measurements, so you need to look at a chart for every garment you want to buy!

This chart gives you an idea of the typical measurements used for blazer sizes, but this will vary from one clothing company to another.

Size Chest Waist Hips Sleeves
4 32” 27” 34” 23.5”
6 34” 27” 35” 24”
8 36” 30” 37” 24.5”
10 38” 32” 39” 24.5”

Men’s Blazer Size Chart

Once you pin down your own blazer measurements, you can compare them to the sizing chart for the garments you want to buy.

This chart gives you an average idea of the measurements often used for men’s blazers:

Size Chest Waist Hips Sleeve
34 34” 28” 36” 32”
36 36” 30” 38” 32”-33”
38 38” 32” 40” 33”-34”
40 40” 34” 42” 34”

Suit Jacket Size Calculator

You can also get a quick estimate of your typical blazer size using a suit jacket size calculator online like this one. This free tool asks you to input your build, height, and weight, and then it guesses what size of a jacket will fit you best based on this information.

Does this work? Well, yes and no. It will give you the average size you will often fit. But as you now know, you can find lots of variations in the precise measurements used to determine size from one brand to another, so there is no guarantee that the calculated size will always fit you from every brand of blazers out there.

Do You Need to Size Up for Blazers?

You do not need to size up for blazers in most cases, as it is always better to take precise measurements and buy a jacket that matches your measurements. You do not need to buy a blazer in a bigger size than you would a shirt, for instance.

On the other hand, you can always get a blazer tailored a little smaller if necessary, and you can’t easily make the garment any larger. So if you do not know how the jacket will fit you, you may want to get a blazer one size up and take it to a tailor for any necessary alterations.

Do Blazers Fit Differently from Suit Jackets?

Blazers have a looser, less formal appearance than suit jackets and will often fit a bit differently because of this.

Blazers often include more fabric than suit jackets and have a less tailored fit. This allows you to wear sweaters, turtlenecks, or blouses under a blazer–you typically only wear a button-down dress shirt beneath a tighter-fitting suit jacket.

Blazers also often have a slightly shorter length than suit jackets, ending somewhere in the top half of your seat rather than covering your whole seat like a formal suit jacket.


The best way to find your blazer size is to take accurate measurements and compare your numbers to the measurements listed in a sizing chart. Key blazer size measurements include the chest, waist, and hips for both men’s and women’s blazers. Measuring jacket length, sleeve length, and shoulder width can also help you find a precise fit.

Blazers have a less formal appearance than suit jackets and should fit you more loosely, allowing space for you to wear bulkier sweaters or shirts beneath the jacket. For this reason, you should put two fingers between your body and the tape as you take your measurements for a blazer size.