I love a sleeve with a smooth, fitted cap. There is something about that clean vertical line at the shoulder, the rounded top of the cap, the tiny inset lines of increase or decreases — it all works for me. I can appreciate sleeves of many types, but the set-in sleeve is my favorite.

Most of the time, set-in sleeves are knit upward from the cuff. When you get to the underarm, you bind off at least an inch of stitches on each side, then decrease at each end of every right-side row until about three inches of stitches remain. At that point, you rapidly decrease the rest of the stitches (usually double the established rate of decrease) and bind off the final inch and a half. This makes a bell-shaped sleeve cap that has fewer rows than the arm opening, so that the flattened top of the sleeve cap can be eased into the shoulder.

If that doesn’t make a lot of sense to you, written out like that, well, join the club. There is something a tad mystical and perplexing about how set-in sleeves work and how they can be made to fit —at least for those of us (including myself!) whose ability to understand things spatially is somewhat deficient. Would a picture help?

There’s a lot to recommend the classic approach to knitting set-in sleeves. But what if, say, you’re knitting a sweater with a bag of random balls of yarn that you bought off eBay because you were charmed by the handwritten tags identifying them as the natural-dyeing experiments of a crafter from the 1960s?

And what if you’ve knit the front and back but haven’t weighed the yarn, and eyeballing it suggests you have enough for sleeves — probably — but definitely not enough for full-length sleeves, and you want to use every single meter of available yarn, but you super don’t want to run out of yarn a few inches from the top?

In that situation, top-down sleeves are your new best friend. Just knit those sleeves for as long as you can make it work, and when you start to run out of yarn, change gears and knit cuffs. Ta-da! You have a sleeve of exactly the right length — which is to say, you have a sleeve of a length that reflects however much yarn you happened to purchase.

Of course, when I say “you” here, I mean “me.” I know you didn’t buy that eBay yarn lot, because I did. I am the only person who would get myself into that particular situation. But you might find yourself wanting to maximize sleeve length without running out of some precious yarn of your own choosing, and top-down sleeves are perfect for that scenario.

Knitting set-in sleeves from the top down is also handy if you’re designing your own sweater and your visual planning is less than fantastic. I have made many sleeve caps, yet I can’t say that I exactly understand at a cellular level how they fit into armholes. I do have faith, however, in my ability to figure out as I go whether or not something is working. Knitting a sleeve cap right into the spot where that sleeve cap belongs is a very satisfying activity for me. When it isn’t working, I can see what’s gone awry, rip it back, and try again. And it’s only a sleeve cap, after all — hardly more than a swatch’s worth of material — so my experiments rarely take longer than an hour to go off the rails.

Hopefully I have convinced you to give top-down set-in sleeves a try.

All Right, Let’s Do This

First things first: How big do you want your sleeves to be? The measurement you need is the circumference of the sleeve around your upper arm, right at the underarm.

You can arrive at this measurement in a many different ways. If you’ve made a sweater in the past that you adore, you can take the upper arm circumference from that sweater’s pattern, or you can measure the sweater itself. You can also measure a non-handmade sleeve that fits the way you want your new sweater to fit. Even if your reference garment isn’t quite what you want for this project, it’s fine to add or subtract from the reference measurement to guesstimate the right fit. Or you can get wild and measure your actual arm, adding or subtracting from that measurement to adjust for how you want this sleeve to fit.

Got your ideal sleeve circumference figured out? Good. Write it down.

The second number you need is your stitch gauge. You probably already know this from your swatch, or from knitting the front and back of the sweater. If you don’t know it, go ahead and measure how many stitches you get per inch (or per centimeter — so long as you measure everything in the same units, it doesn’t matter which units you use), making sure this gauge reflects the yarn and the stitch pattern you’re planning to use for your sleeves. Don’t be afraid of fractions. If you get 21 stitches over 4 inches, for example, your stitch gauge is 5 1/4 stitches per inch. Write it down.

Now you’re going to multiply your desired sleeve circumference by your stitch gauge. This gives you the total number of stitches around your sleeve cap.

Desired Sleeve Circumference x Stitch Gauge

=

Total Number of Stitches around Sleeve Cap

Example: Say that my arm measurement at the underarm is 16 inches, but I want my sleeves to be big and blousy, so I am aiming for a sleeve that measures 6 inches bigger than my arm, or 22 inches at the underarm. My stitch gauge is 5 stitches per inch.

22 inches x 5 stitches per inch = 110 stitches

Again, write this number down. It is the number of stitches that you will pick up across your entire sleeve opening — the distance from underarm to underarm in the picture on the left, below.

With me so far? Excellent.

Next, you’ll want to halve the total number of stitches around the sleeve cap. This number is how many stitches you will pick up between the underarm and the top of the shoulder. That’s the opening at the right side of the sweater photo on the right, above.

total number of stitches in sleeve cap / 2

=

number of stitches from underarm to top of shoulder

Example: 110 stitches / 2 = 55 stitches to pick up on each side of arm opening

Again, write the number down.

Then, subtract from this number however many stitches you bound off at one side of the underarm on the body. Later, you are going to pick those up stitch-for-stitch. For the moment, we need to figure out how many stitches are above the bind-off, between the bind-off and the top of the shoulder on one side.

number of stitches on each side - bind-off stitches

=

number of stitches to pick up above bind-off on each side

Example: 55 stitches - 5 stitches at underarm bind-off = 50 stitches per side after bind-off

Got that one written down, too? Excellent.

So the reason we’re doing all this math is that stitches are wider than they are tall. This means you usually can’t just pick up one stitch for every single row around the armhole. Unless you want to knit a sleeve that is considerably wider than your arm measurement, you’re likely going to need to skip some rows. The question is how many? Do you skip every other row? Every third, fifth, seventh row?

The way to finish figuring it out is to count the number of rows in half of your arm opening, starting one row above the bind-off at the armhole and extending to the top of the shoulder. If you look at the picture on the right above, it’s easy to do, because the armhole is striped. Beginning at the orange stripe right above the bind-off, there are exactly 50 rows to the top of the shoulder. This means in my example sweater I will pick up 50 stitches over 50 rows, which I just told you wasn’t likely to be something you want to do, but it will work for me because I do want to make a sleeve that is substantially larger than my arm measurement.

Here’s how that math works:

number of stitches to pick up above bind-off / number of rows above bind-off

=>

round and reduce fraction

=

pick-up ratio of stitches to rows

Example: 50 stitches per side / 50 rows per side =>

1 / 1

pick up 1 stitch for every 1 row

But let’s say I wanted to make a sleeve that is closer in size to my arm measurement, just an inch larger around. My math would look like this:

17 inches x 5 stitches per inch = 85 stitches

85 stitches / 2 = 42.5 stitches per side —> round up to 43 stitches per side of armhole

43 stitches - 5 stitches at underarm bind-off = 38 stitches per side of armhole

38 stitches per side / 50 rows per side —> reduces to 19 stitches / 25 rows —> which is about 20 stitches / 25 rows —> which is 4 stitches / 5 rows

I will pick up 4 stitches for every 5 rows.

check in

These are the numbers you should have so far:

1. Total Number of Stitches in Sleeve Cap

2. Number of Stitches on Each Side of Cap

3. Number of Stitches to Pick Up above Bind-Off

4. Pick-Up Ratio of Stitches to Rows

Time To Knit!

STEP ONE: GET ALL YOUR STITCHES ON THE NEEDLE

If you made the front and back separately, they need to be joined together at the shoulders before you can make your sleeve.

You will be knitting back and forth. I use a circular needle because I like the flexible cord for working in this small, rounded opening, but straight needles also work.

First, pick up the stitches at the underarm. You will pick up one stitch for every stitch you bound off of the body.

Second, using the ratio you worked out above, pick up the stitches between the first row above the underarm and the top of the shoulder.

To make the sleeve in my first example above, I would pick up 1 stitch for every row above the underarm, for a total of 55 stitches (5 at the underarm bind-off + 50 picked up over 50 rows). Or, in my second example of the more fitted sleeve, I would pick up 4 stitches and then skip a row, then 4 stitches again, until I got to the shoulder, where I would count to make sure I had 43 stitches (5 at the bind-off + 38 picked up over 50 rows) on my needle.

Count to make sure you have the right number of stitches. You can fudge a little bit if you’re only off by one or two, but if you’re off by a lot, you might need to try again on picking up stitches (or recheck your math).

Continue down the other side, but in reverse: pick up the second half of your stitches according to your ratio, and finish by picking up the bound-off stitches one-for-one.

You should now have the “magic” total number of stitches for the sleeve cap on your needle.

Huzzah!

Concept: What You’re About to Do

The next step will be to make the sleeve cap. Remember, a set-in sleeve cap is shaped like a bell that is flat across the top. You’ll begin with rows that have many fewer stitches than the rows at the bottom of the bell, and then you will gradually widen your cap as you approach the bound-off stitches at the underarm.

To get the desired bell shape from the top down, you begin by working across the top third of the sleeve opening, centered over the shoulder seam. Then you use short rows to gradually increase the width of the sleeve cap until you reach the underarm bind-off.

Here’s a general overview:

The illustration below shows those one-third, one-half, and two-thirds points on a sleeve cap worked from the top down with stripes. See how the first stripe in the cap makes the bell shape, and the stripes gradually flatten out on the way down?

Let’s Break It Down, Tho

STEP TWO: SETTING UP YOUR SHORT ROWS

First things first: since you worked across the sleeve opening to pick up your stitches, you’ll need to work back on the wrong side for your first row of the sleeve cap. But you’re not going to work all the way back to the beginning of the row. Instead, you’re going to work across the wrong side to a point that is two-thirds of the way across the row.

You know what that means? More math!

Take the total number of stitches around the sleeve cap and divide that number into thirds. Add two of those thirds together. Write that number down. This is the number of stitches you will work before you stop and turn around.

total number of stitches around sleeve cap / 3

x 2

= stitches to get to two-thirds point of sleeve cap

Example: 110 stitches around sleeve cap / 3 = 36.3 stitches x 2 = 72.6 stitches

Round to 73.

I’m going to purl 73 stitches on my first row.

On your way across, place a marker at the halfway point. For me, that’s at 55 stitches.

Now you’re going to turn the short row. There are a lot of different ways to turn short rows in order to avoid making gaps in your fabric. My go-to is the wrap-and-turn method, which puts a little lasso around the base of the next stitch on the left needle. To wrap and turn on a purl row, I take the yarn to the back, slip the next stitch purlwise onto my right needle, bring the yarn to the front again, and slip the stitch back onto the left needle.

After turning the short row, turn the work so the right side is facing you. You should now have two-thirds of the stitches of your armhole opening on your left needle and one-third on your right needle.

Remember, your goal is to work across one third of your stitches and for those stitches to be centered over the shoulder seam. So however many stitches you’ve got on your left needle lying to the right of the stitch marker — which marks the shoulder seam — that’s how many stitches you need to work past the marker before you turn another short row. Or, to say the same thing another way, work across the top of the armhole, slipping your stitch marker, until a third of the total armhole stitches remain on your left needle. Wrap and turn. To wrap from the right side, you bring the yarn to the front, slip the next stitch purlwise onto your right needle, take the yarn to the back again, and turn. Short rows unlocked!

Now that you have the first two short rows in place, begin increasing the width of every row by one stitch. To do this, work across the next wrong side row until you get to the stitch that you wrapped (the one with the lasso around the base of it). Remember, this was the stitch one past the end of your row, so when you work it, you will be adding one stitch to your current row.

You can choose to incorporate that little wrap-lasso, or you can ignore it. You’ll get a slightly different effect depending on which way you go, so feel free to experiment. If you decide to ignore it, purl the stitch with the wrap, wrap the next stitch the way you did before, and turn your work. If you want to incorporate the wrap, you need to pick up the little wrap with your needle from the front side of the work, drape it over the tip of the needle so it is next to the stitch itself, and purl them both at the same time — the stitch and its wrap — as though you’re working a purl two together. Then wrap the next stitch and turn your work.

Do the same thing on the right side, making your row one stitch wider by incorporating or ignoring the wrap and then wrapping the stitch after it. To incorporate the wrap from the right side, pick the wrap up on the right side with your right needle from underneath and drape it over the left needle beside the stitch. Knit them together through the back loop, then wrap the next stitch and turn.

Keep going on like this, incorporating or blowing right past your wraps, adding one stitch to each row, and watching your sleeve cap grow until you have added back all the stitches of the original row to your needles except for the underarm stitches that you picked up from the bound-off ends of the row.

On the next row, incorporate or blow past your wrap and then keep working even to the end of the row. Turn and work all the way across to the end of this row, removing your stitch marker and incorporating the final wrap.

You’ve made a sleeve cap!

STEP THREE: NOW MAKE A SLEEVE

From here, you can finish the sleeve however you’d like. You have lots of options, but I’m only going to dash through a few of them because I have to end this tutorial sometime, and this seems like as good a place as any.

First decision: Do you want to continue working your sleeve back and forth, or do you want to switch to knitting it in the round? To work in the round, you’ll need a circular needle smaller than your sleeve circumference, as well as a plan (double-pointed needles, two circulars, or a circular with a very short cord) for dealing with the reduced circumference as you get toward the cuff. I generally avoid the hassle by knitting my sleeves flat and seaming them at the end, but I like seaming.

Second decision: What kind of sleeve do you want to make?

The easiest sleeve is probably the one I made, a sort of semi-balloon sleeve. I just worked straight down without any decreases until I got to the cuff. Then I decreased rapidly by working knit two, knit two together across one entire row. I did that on three sets of right-side rows until I had the number of stitches I wanted for the cuff. Then I worked the cuff in ribbing and bound it off.

If you don’t want a ribbed cuff, you can do a hem. Work to the end of your sleeve, purl a row, and then go down a couple needle sizes and work about two inches in stockinette. Your purl row becomes a turning row, and you sew the hem down on the inside.

If you want a more traditionally fitted sleeve, you’ll need to decrease the width as you work your way toward the cuff. As a general rule of thumb, work about two inches before you start decreasing. Then take off one stitch from each side about every inch until you reach the cuff. Sometimes you’ll have to decrease more rapidly as you get closer to the cuff — work a decrease row every half inch instead of every inch or decrease four stitches on every decrease row instead of two.

There are ways to apply more precise math to this situation, but you can also drape your sleeve-in-progress over your arm and eyeball it, and I find that works just as well or better a lot of the time.

Refinements

This approach to a top-down sleeve won’t work in all yarns, for all projects, or for all people. Here are a few refinements to think about if your cap is going off the rails.

• Reconsider the ratios. The division of the armhole opening into thirds might not work for your project. If you want a flatter, smoother top to your sleeve cap, try adding more stitches to that central portion. Or, if the top of the cap feels wide or bulky, try reducing the number of stitches you work there.

• Adjust the rate of increase. On a sleeve cap worked from the bottom up, it’s customary to decrease one stitch at each edge of every right side row until about three and a half inches of width remain, then decrease twice as rapidly over the next two inches. On a sleeve that has more ease and is knit using this method, the rapid decreases might begin lower down, when four and a half or even five and a half inches remain. The top-down method of this tutorial doesn’t include any rapid increases in the first few inches. You may find that it works for you to add two stitches per right side row for the first few inches before slowing down the rate of increase for the remainder of the sleeve cap.

• Stop increasing sooner. How many short rows you work determines the depth of the sleeve cap. You might like the look of your cap better if, instead of working short rows all the way up to the bound-off underarm rows, you stop the short rows an inch or two sooner, or incorporate those last sets of stitches before the underarm at a more rapid pace.

Final Thoughts

I hope this tutorial has given you the confidence to try a set in sleeve from the top down! The stakes are low. No one will die if you get it wrong. Have at it, and let me know how it works out!

If there are things you still want to know about top-down sleeves — or anything else — you can also submit questions through the Fit Desk form, and I’ll try to answer them in a future post.