I know,
I know, you’ve just bought some lovely yarn and a new pattern, and you want to
cast on right away. Why bother with a gauge swatch?
Every
knitter is different. Even though a pattern says that the stitch gauge is 18 sts/4”
with size 8 needles, you may need size 9 needles to get that gauge, or size 7.
Or size 6. The only way to know is to knit a sample and measure it. It matters
because this determines the fit of your garment. If you are, say, casting on 200
sts for a sweater, and the stitch gauge is 18 sts/4”, the garment will measure
44.4” around. What if, with that same yarn and the indicated needle size, you
get 20 sts/4” (which is 5 sts/inch instead of 4.5 sts/inch)? Your sweater will
be 40” around instead of 44.4.” Your comfortable sweater just got tight.
To make
a gauge swatch, knit a square using the yarn you plan to use and the needle
size you think you’ll need. The larger
the better, though 6x6” is a good size. The pattern will tell you what stitch pattern
was used to measure gauge; if it says “gauge in st st” (stockinette stitch),
then knit your gauge swatch in stockinette stitch. If it uses a different
stitch pattern to measure gauge, it will tell you which one to use. Gauge is
expressed in sts (stitch gauge) and rows (row gauge) per 4.” When the swatch is
big enough, pull the needles out. Place a pin at each edge next to the selvedge
stitches (don’t include them, as they are often distorted) and measure the
number of inches between the pins (include fractions). You’ll get the most
accurate measurement using a ruler rather than a flexible tape measure. Then
count the stitches between; knit stitches appear as Vs, so count the Vs.
Convert this number to sts per 4”. This number is your stitch gauge; it is the
more important of the two measurements because it determines how big around
your garment will be. Next, measure row gauge: place pins top and bottom, not
including the cast on edge nor the last row (whether bound off or live
stitches). Measure inches and count rows, and convert to rows per 4”. Row gauge
is less important, as length in patterns is usually measured in inches rather
than number of rows. You will need to wash the swatch and then re-measure to
get your final gauge, but this will be a good approximation.
If your
stitch gauge is a higher number than that given, then your stitches are too
small (more stitches in an inch), so you need to use a larger needle, and vice
versa. If your stitch gauge is off, decide whether you need to up or down in
needle size, and try needles one size different. Rather than starting another
swatch, you can put the new needle into the stitches at the top of your swatch.
Purl a row on the front to create a dividing line, and keep knitting stockinette
(or whatever stitch pattern was used to determine gauge) with the new needles
for a few inches more. Pull the needles out, and measure again; change needle
sizes again if you need to. Once you have the correct stitch gauge, you are not
done yet; you need to make sure you will still have gauge once it’s washed. It
usually doesn’t change, but it’s possible that a yarn will shrink or grow after
being wet, and if that’s going to happen, you need to know. Wash your swatch
the way you will wash the garment (I like to use a wool wash that doesn’t need
rinsing), then lay it out or pin it out, let dry, and re-measure.
Save
this gauge swatch. If you need to pick up stitches on your garment for a button
band or neck band, or have to work an edging you’ve never done before, you can
practice on the gauge swatch. If you run short of yarn, you can always unravel
it later.
Must you
always do a gauge swatch? No, only when the size of the project matters. If you
are making a bag and don’t really care how big it is, then no, you don’t need
to, but if your gauge is way off and you make it a lot bigger than the pattern
calls for, you may run out of yarn.
Don’t
think of a gauge swatch as a chore; think of it as a chance to play with your
new yarn and ensure that your garment will fit well. A one-day delay to do this
saves you wasting months of knitting, and a significant chunk of your yarn
budget, on an ill-fitting garment.