Raglan Knitting: Top-Down vs Bottom-Up Construction

TL;DR — The short version

Both top-down and bottom-up raglan sweaters use the same shaping maths: four seam lines, each gaining one stitch on each side per shaping round, for 8 stitches per round total. In top-down you start at the neck and work increases outward to the underarm. In bottom-up you work the pieces separately, increase along the raglan seams toward the neck, then seam. The stitch counts at each end are identical; only the direction and operation (increase vs decrease) differ. Top-down is easier to try on as you go; bottom-up gives more control over fit at the shoulder.

What Makes a Raglan a Raglan

The defining feature is the diagonal seam line. In a traditional set-in sleeve, the body has a shaped armhole and the sleeve has a curved cap that sews into it at the shoulder. In a raglan, there is no separate armhole. Instead, the front and back panels taper toward the neckline at an angle, and the sleeve fills in the diagonal space between them. The result is a seam that runs from the underarm to the edge of the neckline — the four raglan lines, two on each side of the body.

Because the sleeve and the body share the same diagonal seam, both pieces can be increased (or decreased) together on the same round. That shared rhythm is what makes raglan math clean and what allows the entire yoke to be knit in one piece rather than assembled from separately shaped panels.

The Four Seam Lines and the 8-Stitch Rule

A raglan yoke has four seam lines:

1. Back panel — left sleeve (left raglan)
2. Left sleeve — front panel (left front raglan)
3. Front panel — right sleeve (right front raglan)
4. Right sleeve — back panel (right raglan)

On each increase round, every seam line gains one stitch on each side (worked as a make-one or yarn-over to the left and right of a seam stitch or seam marker). That is 2 stitches per seam line, times 4 seam lines = 8 stitches total per increase round. This is true for every top-down raglan regardless of size, yarn weight, gauge, or pattern. The schedule varies (how many rounds apart the increases are), but the amount per round never changes.

The 8 stitches split predictably: 4 go to the body (2 to the front, 2 to the back) and 4 go to the sleeves (2 to the left sleeve, 2 to the right sleeve). In a bottom-up raglan, the same 8 stitches are removed per decrease round as the yoke converges on the neck.

Top-Down Construction

In a top-down raglan you cast on at the neck, place markers to separate back, front, and two sleeves, and begin working increases. The cast-on divides into four sections (back, front, left sleeve, right sleeve) with the proportions typically around 30% back, 30% front, and 20% per sleeve. A 16-inch neck at 5 stitches per inch = 80 stitches, split into 24-back, 24-front, 16-left, 16-right (with minor rounding).

Every increase round (usually every other round to keep the diagonal angle at roughly 45 degrees) adds 8 stitches until the body sections reach the underarm stitch count. At the underarm, you place the sleeve stitches on holders or scrap yarn, cast on a small number of underarm stitches to complete the body tube, and continue the body downward to the hem. Later, you return to the sleeve stitches, pick up the underarm cast-on stitches, and work the sleeve downward with a taper.

One practical advantage of top-down: you can try the sweater on at any point before finishing the body. Slip the stitches onto waste yarn, slide the piece over your head, and check the chest and yoke fit with no seaming yet done. This catch-early benefit is why many modern independent patterns default to top-down construction.

Bottom-Up Construction

In bottom-up construction you knit the front and back as separate flat pieces from the hem to the underarm, then join them on one needle to work the yoke in the round. At the joining row (the underarm), you place a small number of stitches on hold for the seam and begin working decreases at the raglan seam lines. Each decrease round removes 8 stitches in total — the same count as top-down, but in reverse. The yoke converges toward the neck over the same number of shaping rounds as a top-down version would use for increases.

Sleeves in bottom-up are knit separately from the cuff upward, tapered to the upper arm, and then joined at the underarm when the body pieces are joined. All four sections (back, front, left sleeve, right sleeve) then decrease together on the same rounds through the yoke until the neckline stitch count is reached, at which point you bind off or pick up and work neckband ribbing.

The main advantage of bottom-up is control over the shoulder width. Because the front and back are knit flat, the designer can vary the width of the front vs back, the placement of the underarm divide, and even the slope of the raglan line independently per section. Top-down in the round constrains you to symmetric shaping on every increase round; bottom-up flat sections can be shaped row by row.

The Shared Maths

Whether you go top-down or bottom-up, the two anchor stitch counts are the same: the neck stitch count (where the yoke is narrow) and the underarm stitch count (where the yoke is wide). The number of shaping rounds is always:

Shaping rounds = (underarm total stitches − neck total stitches) ÷ 8

For a concrete example: neck 80 stitches, target body underarm 200 stitches (front + back) plus two sleeve sections of 60 stitches each = 320 total at underarm. The difference is 320 − 80 = 240 stitches, divided by 8 = 30 increase rounds. At every-other-round cadence that is 60 rounds total for the yoke, which at 7 rows per inch is about 8.6 inches of yoke depth.

The same 30 rounds, worked in reverse with decreases, gives the same yoke depth in a bottom-up version. The stitch counts at the beginning and end are identical; only the direction of travel differs.

One nuance: the section stitch counts at the underarm differ slightly between the two constructions because of how the underarm cast-ons work. In top-down, you cast on a small number of underarm stitches (typically 6 to 10, corresponding to about 1 to 1.5 inches) when you separate the sleeves from the body, which adds stitches that were not part of the yoke. In bottom-up, those same stitches are held, not added. The raglan calculator accounts for this: it takes your desired underarm span in inches and converts it to stitches, then adds them when computing the body closure check.

Increase Cadence and Yoke Depth

The increase cadence (how often increase rounds occur) determines the angle of the raglan line and the depth of the yoke. The two standard options:

• Every other round (the default) — one increase round, one plain round, repeat. This is the classic raglan cadence. At a typical ratio of 5 stitches per inch and 7 rows per inch, it produces a diagonal line that reads as a roughly 45-degree angle in the fabric.
• Every round (less common) — an increase on every round, which produces a steeper line and a shorter yoke for the same stitch count. Used occasionally for extra-fast-growing yokes or when the gauge ratio calls for it.

Yoke depth in inches is a derived value, not an input. It is determined by the number of shaping rounds times the cadence interval times rows per inch:

Yoke depth = shaping rounds × rows per shaping interval ÷ rows per inch

At every-other-round cadence, rows per shaping interval = 2. So 30 increase rounds × 2 rows ÷ 7 rpi ≈ 8.6 inches. A classic rule of thumb is that yoke depth should be about 18 percent of the finished chest circumference. For a 40-inch finished chest that is 7.2 inches; for a 48-inch chest it is about 8.6 inches. When yoke depth and chest target come into conflict — the maths wants 9.5 inches of yoke to close the chest, but 8 inches is the maximum before the sleeves are too long — the closure check in the raglan calculator flags this and suggests an adjusted yoke depth.

Raglan vs Set-In Sleeve

Raglan and set-in sleeve are the two most common sweater constructions in knitting, and the choice between them affects both how you knit the piece and how the finished garment fits.

In a raglan, the sleeve extends all the way to the neckline. The top of the sleeve and the top of the body panels form the whole yoke together. This means the yoke gives you no separate shoulder seam: the diagonal raglan line runs directly from underarm to neck, so there is no horizontal shoulder seam across the top of the sweater.

In a set-in sleeve, the body has a shaped armhole that defines the shoulder line precisely. The sleeve has a curved cap that fits into that armhole. The cap shaping (a series of bind-offs followed by decreases, then final bind-off) needs to match the armhole depth exactly, which is where most of the set-in sleeve maths lives. The set-in sleeve calculator handles the full taper and cap schedule given your cuff, bicep, and armhole-depth measurements at your gauge.

Raglans are generally more forgiving: one gauge error in the yoke adjusts automatically because the yoke is a single piece. Set-in sleeves require the body armhole and the sleeve cap to match exactly, which demands more precision. The trade-off is fit: a set-in sleeve gives a cleaner shoulder line and often a better fit for those with narrow or sloping shoulders, because the shoulder seam sits at the exact shoulder point rather than sloping across it.

Which Construction to Choose

Choose top-down raglan when:

• You want to try the sweater on as you go and adjust length before you bind off.
• You prefer minimal seaming (the body and sleeves are worked in the round with no side seams).
• You are new to sweater construction and want a single, continuous piece to follow.
• You are resizing a pattern or working from your own measurements, because the cast-on and yoke are one place to set the whole garment.

Choose bottom-up raglan when:

• You want to knit the front and back flat (useful for complex stitch patterns that are easier to read on the right side only).
• You prefer to work from a familiar "bottom to top" sequence familiar from flat knitting.
• You want more design control over the angle and placement of the raglan line per section.

Choose set-in sleeve (instead of raglan) when:

• Shoulder fit is critical — set-in gives a more tailored look, especially for fitted styles.
• The design has a structured shoulder line (shoulder pads, exaggerated shape).
• You want to mix yoke and body construction (e.g. a cabled yoke that is separate from a plain body).

Also see

These articles cover topics that run alongside raglan construction:

• Sweater pattern resizing — the complete guide to rescaling a sweater pattern to any size or gauge, including a worked example that walks through resizing a top-down raglan from a 38-inch chest to a 44-inch chest.
• Knitting maths — the foundational guide to gauge, stitch counts, shaping, and yardage. Covers the sleeve taper maths and how to spread shaping rows evenly, both of which appear in raglan construction.
• Cast-on & raglan walkthrough — worked examples for top-down raglan cast-on calculations and stitch-multiple rounding.
• Increase & decrease calculator — even-spacing calculator for the increase and decrease rows in a raglan yoke, and for any "work evenly across" instruction on the hem or cuff.

Frequently Asked Questions

Why do raglan increases always add 8 stitches per round?

A raglan yoke has four seam lines: back-left, back-right, front-left, and front-right. Each seam line gets one increase on each side, which is 2 stitches per seam line. Four seam lines times 2 stitches equals 8 stitches added per increase round. The total grows by 8 each time regardless of the rhythm (every round or every other round).

Can I try on a top-down raglan as I knit it?

Yes, and this is one of the biggest practical advantages of top-down construction. Because the yoke and body are knit from neck to hem without seaming, you can slip the piece onto a holder at any point, try it on, and check the chest fit before the body is done. This is much harder in bottom-up, where the front and back pieces are knit separately and seamed before you can check the fit across the chest.

Is the maths different between top-down and bottom-up raglan?

The stitch counts and the shaping rate are the same; only the direction and the operation change. In top-down, you start at the neck stitch count and work increases until you reach the underarm stitch count. In bottom-up, you start at the underarm stitch count and work decreases until you reach the neck stitch count. The number of increase or decrease rounds is the same; you just run the schedule in reverse.

How do I know how deep my raglan yoke should be?

Yoke depth is approximately 18 percent of the finished chest circumference for a classically proportioned raglan. For a 40-inch finished chest that is about 7.2 inches. A shallower yoke (5 to 6 inches) suits closer-fitting sweaters and smaller sizes; a deeper yoke (8 to 9 inches) suits oversized or drop-shoulder styling. The Stitchsums raglan calculator runs a closure check that tells you whether your chosen yoke depth lands at your chest target and suggests a corrected depth if it does not.

What is the difference between a raglan and a set-in sleeve?

A raglan sleeve runs diagonally from the underarm to the neckline, so the top of the sleeve forms part of the yoke rather than fitting into a separate armhole. A set-in sleeve has a curved cap that fits into a shaped armhole sewn (or knit) into the body at the shoulder. Raglans are generally easier to knit and to resize because the yoke is one continuous piece; set-in sleeves give more control over shoulder width and silhouette but require careful cap shaping and assembly.