Top-down raglan sweater calculator

How to use the sweater calculator

1. Measure around the fullest part of the chest. Switch to centimeters if you prefer.
2. Pick an ease preset (close fit +0 in, standard +3 in, relaxed +5 in, oversized +8 in) or type your own ease.
3. Knit and block a swatch in stockinette, then enter stitches per 4 inches. Add rows per 4 inches to see the yoke depth.
4. Set the upper sleeve. 35 percent of K is a fitted sleeve and 40 percent a roomy one.
5. Follow the plan from the neck down: cast on, place markers at the four seam stitches, increase, then separate the sleeves.

How the percentage system works

Elizabeth Zimmermann's idea was that the parts of a plain sweater stay in proportion to the body. Once you know K, the number of stitches around the chest, the rest follows. The neck is about 40 percent of K, each underarm about 8 percent, and the upper sleeve about 35 to 40 percent.

In a top-down raglan you start at the neck with stitches for the back, front and both sleeves, divided by four seam stitches. Each raglan round adds a stitch on both sides of every seam stitch, 8 in all. When the sleeves are wide enough you put them on hold, cast on the underarm stitches and knit the body and sleeves down separately. Because every section grows by the same amount on raglan rounds, the body usually needs a few extra increases of its own. The calculator places them on the plain rounds.

Formulas

• K = (chest + ease) × stitches per inch, rounded to even.
• Neck = 40% of K; sleeve sections = (neck − 4) ÷ 6; front = back = (neck − 4 − 2 × sleeve) ÷ 2.
• Body rounds = (K ÷ 2 − 2 − underarm − neck front) ÷ 2.
• Sleeve rounds = (upper sleeve − underarm − neck sleeve) ÷ 2.
• Raglan rounds = the smaller of the two; extra rounds = the difference.
• Stitches at separation = neck + 8 × raglan rounds + 4 × extra rounds.
• Yoke depth = 2 × the larger of raglan and extra rounds ÷ rows per inch.

Worked example: a 40 inch sweater

A 37 inch chest plus 3 inches of ease is a 40 inch sweater. At 5 stitches per inch, K = 200. The neck is 40 percent, or 80 stitches. Take away 4 seam stitches to leave 76: 13 for each sleeve and 25 each for front and back.

The underarm target is 16 (8 percent) and the upper sleeve 70 (35 percent). Each sleeve needs (70 − 16 − 13) ÷ 2 = 20.5, rounded to 21 raglan rounds. The front needs (100 − 2 − 16 − 25) ÷ 2 = 28.5, rounded to 29, so 8 more rounds increase the body only. That makes the front and back 83 stitches and each sleeve 55, with 280 on the needle. To make the body exactly 200 the underarm cast-on is 15, and each sleeve becomes 55 + 15 = 70. At 7 rows per inch, the 42 yoke rounds measure about 6 inches.

Stitch counts by finished chest

At 20 stitches per 4 inches, upper sleeve 35 percent.

Yoke depth by size, and what to do when it falls short

The yoke depth the calculator shows is the length the increase rounds take. At 20 stitches and 28 rows per 4 inches it grows with the chest:

That is often shorter than the body needs. KT's Slow Closet measures the yoke on the wearer, diagonally from the top of the raglan line to an inch or two below the underarm. It aims for 9 inches in its example. At 7 rows per inch, 9 inches is about 63 rounds, against the 42 the 40 inch example needs for its increases. KT's advice when the stitch counts arrive early is to stop increasing, keep the raglan markers in place and work even until the yoke is long enough. So use the stitch counts from this calculator, and take the length from your own measurement.

Checking the numbers against other methods

Designers split the neck cast-on in different ways. The percentage system gives each sleeve one sixth of the neck stitches after the seams. In the 40 inch example that is 13 sleeve stitches to 25 back stitches, about 52 percent. KT's Slow Closet calls about 30 percent of the back neck the conventional ratio, which would be 8 here, and says the writer likes a higher one. The calculator keeps the percentage-system split, since it works out its raglan and body-only rounds from that split.

The underarm cross-checks well. KT finds 3 to 3.5 inches a good underarm width, and the 15 stitch underarm in the example is 3 inches at 5 stitches per inch.

Raising the back neck with short rows

A top-down raglan starts with the front and back neck at the same height, and the calculator keeps it that way. addi's top-down raglan tutorial adds short rows across the back to give it a few inches of extra length. It works 8 to 12 of them, fewer in thicker yarn and more in finer yarn, with 3 to 4 turning points at each end. Short rows add length to the back without changing any stitch count, so every number here still holds.

The same sweater at other gauges

A 40 inch finished chest, upper sleeve 35 percent. The table takes row gauge as 1.4 times the stitch gauge, the same ratio as 20 and 28.

The yoke depth stays close to 6 inches across these gauges, because finer yarn needs more increase rounds but also packs more rounds into each inch.

Tips for a top-down raglan

• Use a different color of marker for the start of the round so you never lose your place.
• Try the yoke on as you go. Top-down knitting lets you check the fit before you separate the sleeves.
• If the neck feels too wide, knit the neckband on a smaller needle or pick up fewer stitches for it.
• Put the sleeve stitches on waste yarn longer than you think you need, so you can try the sweater on.
• Keep notes of where you placed extra increases. The second sleeve and any future sweater will be easier.