Using a stitch pattern: how many stitches to cast on?

This is part 2 of a series about how to use stitch patterns. (Part 1: the parts of a stitch pattern.) It is extremely basic, and is meant to help get you started. It will not help with sweater design, or with combining multiple stitch patterns in a single object, or other more complicated things.

The first step is to figure out how many repeats of the stitch pattern you want in your object. Yes, this will take arithmetic. Or you can guess and rip out multiple times. That works too, but I personally find it more frustrating. It’s also harder on the yarn.

Ideally, you’ll knit a gauge swatch in the stitch pattern (at least 7 inches/ 18cm square) and wash it so you can measure how many stitches and rows there are over 4 inches / 10cm. This is especially important for something that needs to fit a particular way. Sometimes you can instead start by making a good guess, knitting on your scarf for a while, and then washing it while it’s still in progress to see if the gauge is right. Using the object itself as a gauge swatch is a fairly common practice for small objects. (I use it for mitts all the time.)

For a scarf, you might be able to get away with a rough estimate, based on the gauge listed on your yarn label. For anything really large, or for anything that requires a good fit, I would really recommend the gauge swatch, because any errors in guessing will be multiplied by a lot to make your item too large or too small.

So, here’s how to calculate your number of stitches to cast on based on your gauge swatch.

Sometimes, it’s easier to figure out how many stitches or rows there are over a standard measurement

(For example, 4 inches or 10 cm).

I’m not going to go into gauge measurement in detail; there are a lot of tutorials out there about how to measure gauge like this.

Diagonal rib

For the swatch shown above, spiral rib, stitch gauge was 19 stitches over 4 inches (or 19 stitches over 10cm).

Let’s say you want to make a scarf.

Divide the stitch gauge by the number of units you measured over to figure out how many stitches per inch (or per centimeter), and multiply by the width you want your scarf to be. (Don’t round off the stitches per inch measurement.) Let’s say this scarf should be about 10 inches wide, or about 25cm.

Here’s how to do that math:

(stitches over 4 inches / 4 inches) * (final measurement) =

(19/4) * 10 = 47.5 stitches

Note: you can take this calculation: (19/4) * 10
and plug it directly into DuckDuckGo, or Google, or probably other search engines.

Here’s the metric calculation:

(stitches over 10cm / 10cm) * (final measurement) =

(19/10)*25 = 47.5 stitches

The stitch pattern is a repeat of four stitches, so you should round up or round down to the nearest multiple of four. Which direction you go depends on whether you’re adding selvedge stitches (if working flat), and whether you want the scarf to be at least 10 inches / 25cm, or at most 10 inches /25cm. You might also consider whether you want the scarf to be as long as possible given your yarn (in which case, round down).

The multiple of four that is smaller than 47.5 is 44 stitches. The multiple of four that is larger is 48. Personally, I’d probably go with 48 stitches unless I were adding a selvedge stitch on each edge, in which case, I’d cast on 44 stitches for the stitch pattern, plus two more stitches for the selvedges, resulting in 46 stitches.

Other times, it’s easier to figure out how wide a repeat of the stitch pattern is.

Cables, I’m looking at you. Also lace. Or any other stitch patterns that make it hard to count stitches in a straight line across the fabric.

Journey stitch pattern with a ruler on it to measure repeat width.

Pick a readily identifiable point in the stitch pattern – a halfway point between cables, perhaps. The zero point on the ruler on the lace swatch for Journey above is between two stitches just below a double yarnover. Measure horizontally across a repeat (or even better, across multiple repeats) to the same point, and get as accurate a measurement as you can. Do this in at least three places, and work out the average measurement, if the measurement varies.

My three measurements didn’t vary (but sometimes they do). I got 2 repeats over 4.75 inches / 12cm each time.

Again, let’s say you want a scarf that’s about 10 inches/25cm.

Divide the number of repeats by the measurement you measured them over: in this case 4.75 inches or 12 cm. Multiply the result by the measurement you want for the scarf.

(number of repeats / 4.75 inches) * (final measurement) =
(2/4.75) * 10 = 4.21 repeats

(number of repeats / 12 cm) * (final measurement) =
(2/12) * 25 = 4.17 repeats

This stitch pattern will not fit exactly into the desired measurement, so you need to either round up or round down the number of repeats you want to fit in.

The answers above are closer to four repeats than to five, so that’s what I would suggest using. Sometimes an odd number of repeats is preferable, but this stitch pattern is designed to be offset halfway on alternating repeats, and so there will be a centered stitch pattern all the way up the scarf no matter if you cast on for four repeats or five.

So, four repeats of this stitch pattern, plus selvedges, since a lace scarf is generally worked flat and needs selvedges. (If you wanted, you could put a mesh lace pattern edge on either side between this lace and the selvedges to make the scarf exactly 10 inches / 25 cm).

(4 repeats * 16 stitches/repeat) + selvedge stitches =
64 stitches + 4 stitches = 68 stitches.

Therefore, cast on 68 stitches for this scarf.

Please let me know in comments if any of this is confusing, and I’ll do what I can to help.

Next up in this series, converting flat stitch patterns to work them in the round and vice versa.

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3 thoughts on “Using a stitch pattern: how many stitches to cast on?

  1. I really appreciate this post ’cause “Or you can guess and rip out multiple times.” tends to be me every time >.>

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