Tuesday Tip: How to Measure Armhole Depth

Tuesday Tip copyOne of the things that can make or break a sweater is your armhole depth. If it’s too tight, your sweater will bunch under the arm (not to mention be very uncomfortable), if it’s too loose your sweater can look sloppy.

On my Ravelry group we run video sweater KALs several times a year. The KALs are filled with video tutorials and how tos (exclusive to the KAL participants) and there’s always information on picking the right size.

You can find out more about my video sweater classes here

Video Sweater Patterns

Choosing the right size is the most vital step to a happy sweater, and a very important element of that is understanding . . .

How to Measure Armhole Depth

One of the best things to do to get a great fitting sweater is to measure a sweater that fits you well. However, that does not mean curving the tape measure under the arm.

How to measure armhole depth

  1. Put a straight edge under the armhole
  2. Measure from the shoulder (where the sleeve is seamed into the sweater) straight down.

Here is the small of the Corcoran 2.0 and you can see the armhole depth is 7 1/4″.

This is a finished garment measurement that is your body measurement + ease. The biggest mistake knitters make is in measuring their body. I often see knitters put the tape measure at their shoulder and wrap it around into their armpit. This is not armhole depth, but 1/2 an armscye measurement.

How to measure armhole depth

Do NOT put the tape measure around into your armpit.

When I do this, I get a measurement of  7″ (not my real armhole depth)

How to take your body armhole measurement

how to measure armhole depth

Proper body measurement

  1. Put a needle under your arm
  2. Put the tape measure on your shoulder (where the sweater front would seam to the back)
  3. Drop the tape measure straight down

When I do this I get my actual armhole depth, a little under 6″

So why do we curve around the top of the shoulder, but not under the arm. The answer is in our knitting.

Here’s a tiny sample of an armhole. Notice how the curve of the under the arm is in our knitting

How to measure armhole depth

Measuring depth of armhole sample – 7 1/4″

But the curve along the top of the shoulder is in the seaming of the two straight armholes together.

How to measure armhole depth

This 7 1/4″ sample fits me perfectly, with just a bit of ease for comfort.

To prove the point . . . when I curve my 7 1/4″ armhole depth sample around and put the tape measure around the curve. It measures 8 1/4″

How to measure armhole depth

When I measure around the curve (1/2 armscye) I get 8 1/4″

So . . . if I had measured “armhole depth” by curving the tape measure under my arm and got 7″ and then added ease to that I would choose an 8″ – 8 1/2″ armhole depth – and it would be WAY too big on me.

When I measure the armhole depth properly and get a little under 6″ and then added ease to it I would choose a 7″ – 7 1/2″ armhole depth and it will fit me perfectly.

For more sweater fun, you can still make a great sweater and learn a ton in my sweater classes. To read all the message boards and get sweater help, join my community group.

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  • Wren May 24, 2016   Reply →

    Hi Patty,
    Awesome tip. I have a question. How does this technique work on a top-down raglan? I guess put the sweater flat, and measure from the top of the sleeve (folded). Is is a right assumption.

  • Andrea Miller May 24, 2016   Reply →

    Your photos regarding measuring are making the light dawn – thank you for the CLEAREST explanations I have seen about how and wear to measure to get the expected result!

    One question I have about the style of Corcoran 2.0 – the sleeves look quite tailored, narrow even, and I would like the outcome of the sleeves to be more generously sized to allow for my “mature” bicep dimensions (which are NOT from lifting weights – probably because of not lifting them!). So if I would like a bit less slender or form-fitting look, which measurement will I want to adjust? I imagine adjusting the armhole depth by a wee bit, like a quarter of an inch, may add in just that much more desired ease for the sleeve circumference and emerge as the right size of “cylinder” for the sleeve. Am I on the right track here?

  • Patricia Paulson May 25, 2016   Reply →

    Thank you, thank you, thank you for the clear and concise directions on how to take this measurement. I an looking forward to starting the KAL. I would like to be able to make my gauge swatch ahead of time but do not know how to knit the Rain Drop Lace pattern. Is there a video or written instructions for this? Thanks in advance for your help.

  • Diana June 12, 2016   Reply →

    Will this measurement work for the top down sweaters as well? I see some cute ones, but they all have that dreaded bulge across the top of the breast that makes it look poorly fitted.

  • Eva Lim January 4, 2017   Reply →

    Hi. Thanks for your wonderful tip. What about measuring a halter neck dress? Should I be measuring from the top collar to the point where I take the bust length, in terms for arm hole length?

  • Vicky January 27, 2018   Reply →

    I find it much more useful to measure from the back of neck (center) straight down to the horizontal line (where you’ve put the knitting needle). Just put one tape measure around body in the armpit (knitting needle) and have the patient hold it there, while I measure from center back of neck, straight down to the line. Also note if their shoulders are very sloping, or very square, and also if they are very narrow or broad.

  • Danny June 16, 2018   Reply →

    Please Patty, How can i get the standards for that of mens official shirt ?

    my exact problem is how to know the standard height to start the curve from top of shoulder in a pattern drafting to where i join my lines from the chest width to arrive at where i start my curve for the armhole…

    Please Patty, you could use some patience I am really new to all this.

    many thanks.

  • Davies, F,F, August 6, 2020   Reply →

    Thank you for this write up. Quite educative. Please, does the armhole depth measurement method for sweaters also hold for all fabrics like cotton and silk?

  • vanhunks April 7, 2021   Reply →

    Dear Patty, I am an experienced knitter, but this has always stumped me – measuring armhole depth. Thank you for your extremely clear explanation and visual. Much, much easier to follow now.

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