UNDERSTANDING KNITTING GAUGE

What IS Gauge, anyway?
Why is gauge SO important?
Why is needle size NOT so important?
Can you ever get away with NOT knitting a gauge swatch? 
How to knit a gauge swatch:
Say the gauge you need is 5 stitches per inch... 
If your number of stitches per inch is way off... 
Think of swatching as PLAYING WITH YARN 
If you have needles in sizes from #3 to #9 
Now for the "Hard Stuff" (math - but don’t panic)
The Big Three
Remember...

What IS Gauge, anyway? Sometimes called "Tension", it simply means stitches per inch. It will be different depending on the yarn, needle size, individual knitter, and stitch pattern. In general, the fatter the yarn, the fatter the needle you should use with it, the bigger the stitches it will make, so you will need fewer of them. The thinner the yarn, the thinner the needle you should use with it, the smaller the stitches, so you need more of them.

Why is gauge SO important? Because if you don’t know your gauge, you will not know what size your piece will be. Even ½ stitch per inch off can make a difference. For example, if you are following a sweater pattern that is 40 inches around at a gauge of 5 stitches per inch, you will need a total of 200 stitches (5 stitches per inch multiplied by 40 inches). If your gauge is 4 ½ stitches per inch and you cast on 200 stitches, your sweater will be 44.44 inches around (200 stitches divided by 4 ½ stitches per inch).

Why is needle size NOT so important? Every knitter knits differently. Give 6 people the exact same yarn and needles, and they will knit at least 4 different stitches per inch. When you are looking at a pattern, it is NOT the needle size that matters - it is the GAUGE or TENSION. The person who wrote the pattern might knit more tightly or loosely than you, so the size of needle recommended might be too large or too small for YOU. When you begin knitting a project from a pattern, then, you should knit a gauge swatch, even if you are using the exact yarn called for in the pattern. If you are substituting a different yarn for the one in the pattern, you should ALWAYS do a gauge swatch, even if the yarn is nominally the same gauge as the one in the pattern. Yarns of different fiber, texture, number of plies can knit very differently even if they look similar or even if the average gauge on the skein label is the same (or it may be handspun, or a mill-end without a label, or found at a yard sale,……). After you have been knitting for awhile, you will get a feel for whether you are a tight or loose knitter, which can help in figuring out what needle size you need for a given yarn.

Can you ever get away with NOT knitting a gauge swatch? Yes, sort of…..If you want to knit something where the exact size is not critical, say, a baby blanket, a scarf, a shawl or a Christmas stocking (in other words, things that don’t have to fit exactly), you may be able to go by the average gauge given on the yarn label. OR, if you have knitted a lot with a particular yarn and know exactly what gauge you get with a given needle size, you may not need a gauge swatch. Be warned, though, your knitting tension can change over time, according to how you knit, or even what mood you are in.
If you have a yarn you have never worked with before, though, you should do a swatch, especially if there is no gauge given on the skein label, just to get a rough idea of stitches per inch (you don’t need a baby blanket that will cover a king-size bed).

How to knit a gauge swatch: The larger the swatch, the more accurate your measurement will be. Figure out what will be at least 6 inches worth of stitches with your yarn and cast on that many stitches. Knit a few rows in garter stitch. Keeping an inch-worth of stitches at the edges in garter stitch, work in stockinette stitch for a few inches. (NOTE: If your pattern gives a gauge in a pattern stitch, you must do your swatch in this pattern rather than stockinette). At this point you can measure roughly and see if you are way off. Measure 4 inches, count the stitches (half-stitches, too) and divide this number by 4 (it may be a fraction). This is stitches per inch.

Say the gauge you need is 5 stitches per inch, your inch should look something like this: (see diagram to the right)	(5 stitches per inch, may not be to scale)
(6 stitches per inch)	If you have MORE stitches per inch than your pattern calls for (see diagram to the left), your stitches are TOO SMALL. Try a LARGER NEEDLE.
(4 stitches per inch)	If you have FEWER stitches per inch than your pattern calls for (see diagram to the left), your stitches are TOO LARGE. Try a SMALLER NEEDLE.

If your number of stitches per inch is way off (MORE than 1 stitch per inch too big or small), your yarn and pattern probably don’t go together well. You may not ever be able to get the proper gauge for the pattern. You will either need to find another pattern for the yarn, or another yarn for the pattern. EVERY YARN WILL NOT WORK WITH EVERY PATTERN! There is a range of needle sizes and stitches per inch which work well with every yarn; you may be able to knit a yarn with an average gauge of 5 stitches per inch on a smaller needle and get 6 stitches per inch, but it will be very dense and tight. This might be good for socks, but you wouldn’t want to knit a baby sweater like that.
You may either pick out a yarn you like and find a pattern to go with it (or better yet, make up your own), or pick out a pattern and then find yarn to go with it. In order to find the needle size you must use to get the gauge in the pattern, you will need to do one or more gauge swatches.

Think of swatching as PLAYING WITH YARN. It can give you inspiration, experience, knowledge, ideas. A beautiful yarn that you fall in love with in the ball may be no fun at all to actually knit with - and you’ll never know until you start knitting with it. It’s fun to buy single skeins of yarns just to play with - no finished item that needs to be completed. Try different needle sizes, different stitch patterns (Barbara Walker’s four books of stitch patterns are highly recommended), different color combinations, different yarns knitted together as one strand. Put hangtags on your swatches with yarn name(s), date, needle size(s) and stitch pattern(s) and save them for future reference. If it bothers you to have a lot of knitted squares or rectangles floating around doing nothing, sew them together into a blanket. DON’T BE AFRAID TO MESS AROUND AND / OR MESS UP - IT’S ONLY PLAY!

If you have needles in sizes from #3 to #9, try this exercise: Take some medium size yarn whose label gives an average gauge of 5 stitches per inch such as Brown Sheep Nature Spun Worsted, or Red Heart 4-Ply. On the #3 needle, cast on 30 stitches (it should be tight). Knit a few rows in garter stitch, then a couple of inches in stockinette, keeping 5 stitches on each side in garter stitch, ending with a right side row. Now change to the #4 needle and knit 1 row (making a purl ridge on the right side to show where you changed needles) and knit a few more inches. Keep increasing your needle size and knitting a few more inches, putting a purl ridge between each size, until you have gotten to #9. You should have seven sections. Knit a few rows in garter stitch and bind off. Gently steam iron the swatch and look at it. Measure the middle section, which should be the #6 needle. Is your gauge exactly like what it said on the label? Chances are, not exactly. Study each section. Can you imagine a pair of socks at the smallest or next to smallest gauge? Probably. Can you imagine a sweater knitted at the loosest gauge? Probably not, but maybe a shawl would be nice like that.

Now for the "Hard Stuff" (math - but don’t panic).
Abbreviations used in the formulae:
st(s) means stitch or stitches
in means inch or inches
ga means stitches per inch 
X means times 
/ means divided by

The Big Three
1. If you know how many stitches you have, you can figure out how many stitches per inch you have in a certain width:
(In words) Stitches divided by inches equals gauge
(Abbrev.) sts / in = ga
(Example) 200 / 40 = 5 sts/in
This is the formula you use for figuring out your gauge from your gauge swatch, or from any piece of knitting. Lay a ruler or tape measure down on the knitting, and count 22 ½ stitches in, say, 6 inches. 22.5 divided by 6 equals 3.75 stitches per inch.

2. If you know your gauge, you can figure out how many stitches you need to make a certain number of inches: 
Stitches per inch times inches equals stitches
ga X in = sts
5 sts/in X 40 in = 200 sts
This formula is the basic one you need for designing your own stuff. Say you want to make a scarf that you want to be 8 inches wide. You do your gauge swatch and find out that YOUR yarn on YOUR needles is 4 ½ stitches per inch. So, 8 times 4 ½ equals 36 stitches.

3. If you know your gauge, you can figure out how many inches you will get with a certain number of stitches:
Stitches divided by stitches per inch equals inches
sts / ga = in
200 sts / 5 = 40 in
You have a hat pattern that tells you to cast on 90 stitches. The yarn you want to use for it knits up at 5 stitches per inch. Will it work? 90 divided by 5 equals 18 inches - probably okay for a baby or small child, but too small for most adults. 90 divided by 4.5 stitches per inch will be 20 inches; 90 / 4 sts/in will be 22.5 inches.

Remember:

• The THICKER the yarn, the FEWER stitches per inch.
• The LARGER (THICKER) the needle, the BIGGER the stitches.
• The BIGGER the stitches, the FEWER stitches per inch.
• The THINNER the yarn, the MORE stitches per inch.
• The SMALLER(THINNER) the needle, the SMALLER the stitches.
• The SMALLER the stitches, the MORE stitches per inch.