How to Measure a Men’s Suit Jacket

Members of the Ask Andy Community often ask for instructions on how to measure a men’s suit jacket for a great fit.

More specifically, they want a series of measurements to use when considering a third-party seller’s jacket on eBay or other online exchanges.

This article gives you five simple jacket measuring tips for great-fitting jacket.  It also shows you how to apply them to a purchase you may find online.

Note, this same technique may be used to measure suits (measuring the suit jacket) as well.

Don’t Trust the Tag!

First and foremost, do not rely on the tagged size. I measure thousands of suit jackets and can tell you the tagged size has little relation to the actual fit. One brand’s 38 can be another’s 40.

Instead, take the following five measurements of the best-fitting suit jacket in your wardrobe. Memorize those measurements and use them as a baseline when looking at possible purchases on eBay or other online exchanges.

For your reference, I’m using a (measured) size 42 Hermes sports jacket as an example.

1) Chest measurement

This is the most important part to measure a men’s suit jacket.

It varies the least between brands, cannot easily be changed and, most importantly, determines the size of the jacket.

In general, the tagged size refers to the chest measurement of the individual.

So, if your chest measures 42”, you likely wear a size 42 jacket.

Manufacturers will build 4″ or so of “tolerance” into their jackets to allow for freedom and range of movement. So, a 42 jacket likely measures 46″ in total.

Beware, then, of eBay sellers saying a jacket is a size 42 and it measures 42” in the chest. If that’s true, you are quite squeezed!

To measure the chest of a jacket that fits you well,

  •  lay it on a clean flat surface and button it.
  • Button the second button (from the bottom) only on a two or three button jacket. If it is double breasted, button it completely.
  • Arrange the like the picture below in order to ensure accuracy.

Correct Jacket Chest Measurement

In the first picture, the jacket is lying properly.

Measure Men's Suit Jacket Chest
Correct Chest Measurement

Here, the lapels lay flat, and we’ve stretched enough to give the full width of the chestpiece.

Incorrect Jacket Chest Measurements

Stretched Too Far

In this second picture it stretches too far. We can tell by the way the lapels buckle outward.

So, it gives us an inaccurately large measurement.

measuring your sports jacket - incorrect way
Inaccurate suit jacket measurement due to stretching
Not Stretched Far Enough

In this third picture the jacket is not stretched out far enough. We can tell by the way the fabric bunches at the back. So, we’ll get a too-small measurement.

jacket not stretched

Jacket not stretched far enough

2) Waist measurement

We can measure the waist of the jacket at different points depending on the make. It is usually found, though, at the second button (from the bottom).

The waist measurement is usually 2-4” smaller than the chest measurement.

Measure Men's Suit Jacket Waist

Brands targeting older gentlemen (Hickey Freeman, Kiton, Brioni) are likely 2″ smaller.

Designer jackets for young bucks are about 4″ smaller.

3)  Measuring Shoulder Width

This measurement should be taken from shoulder seam to shoulder seam at the widest point (as pictured).

Measure Suit jacket Shoulder
Correct Shoulder Measurement

4) Measuring Jacket Length

The correct way to measure the length of a men’s suit jacket is from the bottom of the collar melton (under-collar) to the bottom of the coat.

This is shown in the picture below.

Measure suit jacket length

Even so, some sellers will still use the full jacket length as their measurement.

If this is the case, you can usually assume the “bottom of the collar to the bottom of the coat” measurement will be 1.5″ less, with that measurement being the height of the collar.

But, if you’re unclear on which measurement the seller is using (it just says ‘Jacket 30″‘), it’s always a good idea to contact and doublecheck.

5) Measuring Sleeve length

We take this  from the top of the sleeve-at the shoulder seam- to the middle of the end of the sleeve (as pictured).

As you can see, the end of the sleeve is often cut on a slant. So, make sure to measure in a straight line!

Measure jacket sleeve length

All sleeves can be shortened. A jacket with non-functioning buttonholes is fairly easy to fix.

You will, however, likely pay significantly more to shorten a sleeve with functioning buttonholes. This requires skillfully removing the jacket sleeve and then reattaching it.

Some jackets can also have their sleeves made longer. You’ll know how much room you have by feeling underneath the hem of the sleeve.

In many cases, you’ll have an inch or so to work with.

In extreme cases, sleeve facing can also be used. For more detailed information about Facings, please see this article.


We’ve discussed the five most common parts to measure a men’s suit jacket.

It’s important to remember, though, variation occurs with silhouette, brand, and time period of manufacture.

Contemporary cuts by modern designers feature a narrow shoulder, trim chest, and trim waist.

Classic and vintage cuts showcase more drape, a fuller chest, and much less built-in suppression in the waist.

The best way to get a great-fitting jacket is to ignore sizing and instead use this guide to compare a garment you find to your best fitting one. If the measurements match or are very close, you’re in great shape.

Thanks again for reading, and we do hope this is a useful guide.

By Andrew Harris

Don’t forget to check out Andy’s Favorite Brands, and be sure to join us in our online Community for the best men’s clothing & style advice you can get on the internet!