An exposition on everybody's favorite dirty word

Gauge.

Sometimes you might feel that gauge should be a four-letter word.*

Thanks to personal knitting techniques, achieving a designer's intended gauge can be practically impossible, if not downright uncomfortable -- even when using the very yarn indicated by the instructions. Some knitters can find themselves dropping down to tiny, tiny needles in an attempt to compress an aran-weight yarn to fit the tight gauge recited in the pattern. Others tear their hair out because their stitch gauge is right on the money, but they can never get the row gauge to match. Gauge can be synonymous with frustration, agony, and throwing needles across a room.

And sometimes, gauge feels the same way about you. From time to time, advice is offered to a knitter who wants to tweak the sizing of a pattern: "just knit it at a tighter/looser gauge to make it smaller/bigger." While it's true that altering the gauge of a knitted fabric will alter the size of the finished piece, it doesn't always mean that you'll get a finished garment that will fit -- or feel -- as expected. Some people get the relationship between "tighter" and "looser" and increased or decreased stitches per inch mixed up. Others assume that gauge is the answer to all yarn substitutions: if it matches, it must be all right. And a bigger gauge (fewer stitches per inch) doesn't always mean easier to knit. Gauge might be a frustrating concept, but it's also misunderstood.

Knit (and purl) stitches aren't square, they're rectangular. But you knew that already.

What gauge wants you to know

Gauge, and knitted fabric generally, is an anisotropic phenomenon. It behaves differently along its horizontal and vertical directions. Just as knitted fabric stretches differently lengthwise and crosswise, when you change needle size to change your stitch gauge, it does not automatically mean that your row gauge will change proportionally.

And of course, as you've probably already noticed, knit stitches are not square. Viewed from the right side, stockinette can be abstracted to an array of rectangles that are longer than they are tall. This means that adding four stitches and four rows does not add the same amount of width or length to a piece.

There are some cases where knitting does turn out to be roughly square. It could be the choice of a stitch pattern that either compresses the stitch width or elongates the row length, or the use of stranded colorwork techniques, or it could even be the nature of the yarn itself: the knitted fabric might stretch vertically when worn to the point that the length of a single row is equal to the width of a single stitch. But those are exceptions to the general rule that knit stitches aren't square.

	When knitting two or more colors in a stranded or woven technique, such as Fair Isle, the rows tend to elongate with respect to the stitch width. Fair Isle gauges are therefore roughly square. In this swatch, the gauge is roughly 7.5 stitches and 7.5 rows per inch. Had a single strand of this yarn been knit in plain stockinette, these numbers wouldn't have been equal.
	In a relaxed state, this chunky yarn knit on 6 mm (US10) needles yields conventionally "square" garter stitch. But when under the influence of gravity, for example when worn vertically, the garter stitch rows s-t-r-e-t-c-h. If you're thinking of knitting a heavy garter stitch jacket, this could happen to you.

Now, there is some conventional wisdom about garter stitch (knitting or purling every row when knitting flat; knitting and purling alternate rows when knitting in the round) that an equal number of stitches and "ridges" creates a perfect square, making garter stitch a popular vehicle for modular knitting. Because of the alternation of knit and purl rows (when viewed from one side), garter stitch fabric tends to squish the rows together, forming a ridge; each ridge seen on one side of the fabric is actually the result of two rows of knitting. In theory, each ridge, being formed of two rows, occupies a space measuring something between one and two rows of normal stockinette that coincidentally makes the length of each ridge span the same width as a single knit stitch.

This conventional wisdom is true for many; however, there are plenty of knitters who don't experience this phenomenon, and who wind up with a rectangle when they knit an equal number of stitches and ridges. Plus, depending on the yarn, if the knitting is meant to be used vertically (for example, worn on the body), garter stitch will likely stretch downward...so in fact, it becomes even less square. In tiny units, such as in modular knitting, most knitters can achieve or coax their garter stitch into square proportions and keep those proportions by picking up and adding additional modules knit in different directions.

Gauge varies from knitter to knitter. It's not a failing of either the pattern or the individual knitter if the knitter can't achieve the right gauge to match the pattern. It's not uncommon to be able to match a pattern's required stitch gauge spot-on, but to never get the row gauge quite right, or vice versa.

There are a couple of factors that affect knitted gauge. First, there's the degree of tension that is exerted on the yarn as it is looped around the needles. The amount of force varies among individual knitters, and depends on the way the working yarn is tensioned between the fingers, around the hand, around back of the neck, through a safety pin, or however the working yarn end is managed. It also depends on the knitter's state of mind at the time. You may have heard, or discovered for yourself, that your gauge can tighten up when you're feeling tense or upset. It's true; it's also possible that with experience and time, your own individual tension will increase or decrease, or that the tension you exert on the yarn will depend on its composition: you may inadvertently exert more (or less) tension on a spongy wool yarn than on an inelastic cotton yarn.

The other factor is the method of knitting: how you hold your needles and how you wrap your yarn around the needles, and whether you form your stitches on the points of the needles or not. If you work your stitches at the very points of the needle, the stitches formed will be tighter than if the stitches are formed on the needle shaft. If you regularly experience difficulty sliding your newly made stitches along the needle, this may be the reason.

Just because the yarn label states a particular gauge doesn't mean it's the best choice for that yarn. Your own experience may have told you that some yarns, such as bulky twisted singles of wool, pill rather quickly when worn unless knit tightly. Or that knitting a yarn to the gauge stated on the label results in a rather floppy fabric, when you'd prefer a firmer feel.

Designers may take a bit of licence in setting gauge. It's possible that they may simply use the gauge chosen by the manufacturer, and then design on paper based on those numbers. Then, when the sample is knitted up, the sample or test knitter needs to match that gauge. It's also possible that the designer -- especially if his or her process involves creating the prototypes or swatches herself -- will simply knit to whatever gauge is pleasing or suitable to him or her, which will not necessarily match the label gauge. In those cases, you'll often find that the pattern gauge is different from the label gauge. However, the label gauge is may still be given in the pattern as a guideline for selecting yarn for knitting the design, because it helps the knitter find suitable substitutes.

Gauge is not permanent, except in special circumstances. Take a swatch or other piece of knitting, grasp it at the side edges, and pull. The fabric gets shorter vertically, the more you pull horizontally. Grasp it at the top and bottom edges, and pull again. The fabric narrows as you increase tension. As you probably know by now, when you take your knitted fabric off the needles, it often doesn't match the required finished dimensions until it's been subjected to blocking.

However, blocking is only a formal application of heat and/or moisture plus tension, potentially resulting in a change in gauge. Heat, moisture, and tension are also applied to your garments as you're wearing them. Ever notice that knitted elbows start to bag? Or that a cotton or rayon knitted top starts out at a hip-grazing length in the morning, but reaches your knees by the end of the day? You can't always assume that once you've set the knitted fabric by blocking, it won't change. As a general rule, the less resilient and the more inelastic the yarn is, the more likely it is to sag and droop with wear.

Same yarn, different needle sizes. But the stitch and row count does not change proportionately with a change in needle diameter.

Increasing the yarn thickness or needle size does not automatically increase the stitch and row gauge proportionally. And simply changing needle size does not mean that the dimension of each stitch will change proportionally. If you increase the needle size used to knit a swatch, it doesn't automatically mean that a 10% change in the width of the swatch will result in a 10% change in the height of the swatch. Because knitting more tightly or loosely can alter the drape of the fabric, when the swatch is blocked or when the knitted fabric is worn, the fabric itself can behave differently. For example, when knit loosely, the fabric may stretch more in the vertical direction than it would have when knit might tightly.

In the photograph at right, the same yarn was knit (from top to bottom) using 2.75, 3.75, 5, and 6 mm (US2, 5, 8, and 10) needles. With 2.75 mm needles, the gauge started out at 5.5 stitches and 8.5 rows per inch; upon switching to 3.75 mm needles, the gauge became approximately 5 stitches and 7 rows per inch. In other words, the stitch gauge changed by 10%, and the row gauge changed by 17%. Upon switching to 5 mm needles, the gauge changed to 4.25 stitches and 5.5 rows per inch: a change from the 3.75 mm needle gauge of 15% in the stitch gauge and 21% in the row gauge. Finally, on 6 mm needles, the gauge became 4 stitches and 5 rows per inch, or a change in stitch and row gauge of 6% and 9%, respectively. With each needle size change, the stitch gauge and row gauge changed by different amounts.

And in the same vein, angles of increases and decreases are not necessarily preserved when you change your gauge. Some other conventional wisdom about resizing a pattern is to change the gauge: if a sweater knit at 5.5 stitches per inch is a little too tight, bumping the gauge up to 5 or 5.25 stitches per inch might give the right amount of breathing room. Right?

The general rule is true, because it's simply math: if you have a fixed number of stitches, and you make each stitch bigger, then the result will be bigger than the original.

But there are other potential consequences to be considered. If you're changing your stitch gauge, chances are your row gauge will change as well. You'll need to compensate for the change in length that will result, which is easy enough for rectangular shapes -- for example, if the body of a sweater is to be worked until it measures 14 inches from hem to underarm, 14 inches is 14 inches. However, the curves and corners that you create by decreasing and increasing (for example, at armscyes, sleeve caps, and necklines) may wind up being a different shape than originally intended.

Let's say that your pattern instructions direct you to create a sloped edge by decreasing 1 stitch every row over 10 rows, 10 times: a total of 10 stitches decreased over 10 rows. When knit at 5.5 stitches and 7.5 rows per inch, that's 1.8 inches difference horizontally, and 1.33 inches vertically, or a length of 2.25 inches forming an angle of 36.26 degrees with the horizontal.

But if you decided to resize your pattern by changing your gauge to 4.5 stitches and 6 rows per inch, you'd wind up with 2.2 inches horizontally and 1.6 inches vertically, or a length of 2.72 inches forming an angle of 53 degrees.

This difference may have an impact on the way your garment is put together, causing seams to not fit together correctly, or altering the pitch of the sleeves when they're joined to the garment. The difference may not be significant, and thanks to the stretch of knit fabric, you might be able to fudge it; but there are circumstances where changing the stitch gauge and not altering the pattern can potentially result in a misfitting garment.

Dealing with the stress of tension

Knowing just how uncertain and variable gauge can be, from yarn to yarn or knitter to knitter, what do you do to ensure that your finished knitted product is up to the pattern specs?

Dress your swatches in the appropriate manner. (Yes, this implies that you've knit a gauge swatch. You've been lectured before, so we won't reprise that lecture here.) Because gauge isn't permanent and can even change with wear, simply whipping up a gauge swatch and measuring it straight off the needles won't prevent unwelcome surprises. Even steam- or wet-blocking your swatch on a flat surface will not guarantee that the finished fabric will keep your measured dimensions.

A solution to this problem is to not only launder and dry your swatch in the manner that the finished garment will be treated, but also to "dress" the swatch by allowing it to hang vertically with additional weight suspended from it, the way that swatch would be treated if it formed part of the fabric hanging from the wearer's body. Think about it this way: if you had knit a 6-inch square (15 cm square) swatch, it might block (flat) to a 6-inch length. But if that piece of fabric were actually located somewhere near your shoulder in a sweater that measured 21 inches (53 cm) in length, there would be effectively another two-and-a-half swatches hanging below your swatch. Not only would your 6-inch swatch, in real life, be subject to the effects of gravity on itself, but it would also be expected to support the weight of another 15 inches (38 cm) of knitting below it. If you simulated the effect of gravity and the additional weight on your swatch, you'd have a more accurate prediction of how the fabric will behave with normal use.

If you want to try dressing your swatches vertically, first launder and dry a generously-sized swatch they way you would the finished article (you'd probably let it dry flat). Weave a thin knitting needle through the stitches along the top edge and bottom edges of the swatch. Clip or tie the needle at the top edge to a clothes hanger, and hang it up. From the needle along the bottom edge of the swatch, suspend the rest of the ball of yarn that you had used to knit your swatch (a good enough approximation of weight -- you don't need to be obsessive about calculating the amount of weight to be suspended). You can hang your remaining yarn by threading a piece of waste yarn through the middle of the ball, and tying the waste yarn to either end of the bottom needle. Let the whole assembly hang freely for a day, then measure the gauge again.

You'll likely find that fabrics knit from slippery and non-elastic yarns, like ribbon yarns, cottons, and silks, are more likely to experience a gauge change, as well as fabrics knit in stitch patterns that stretch easily in the vertical direction (like garter stitch). Swatches in rougher or more elastic yarns, like wool yarns, are less likely to change gauge when dressed.

Yes, physics dictates that if the fabric representing your swatch was located at the hem of the garment, it wouldn't be stretched out so much because it didn't have to support any other fabric. A complete model of how the fabric would behave under realistic conditions is really better suited to a second-year university physics course, so we'll just leave that for now. The point to take away is this: if you replicate the actual conditions under which the fabric will be used, you won't be taken by surprise when the garment stretches out to a different shape.

If you can never seem to match the row (or stitch) gauge, try changing your knitting tools or technique to change your gauge... First, assuming you've knit and dressed your gauge swatches as appropriate, but were still unable to meet both stitch and row gauge, your first Plan B to try to make gauge is to switch needles. Yes, you likely tried a number of different needle sizes in an attempt to match the pattern gauge -- but did you try the same needle size in different brands or materials? Just because you've got two pairs of needles that are labeled to be the same size doesn't mean that they are the same size, particularly if they're made by different companies. If your gauge is slightly off using Brand A, size X, you might just luck out using Brand B, size X.

Also, some yarns and/or fibers are a lot easier to handle with bamboo needles, while others slide better along plastic or nickel; and some yarns and stitch patterns benefit from a higher coefficient of friction between the fiber and the needle, keeping the stitches in place while you execute tricky maneuvers. Switching from metal to plastic to wood when swatching may affect your gauge as well.

If you're primed for adventure or you're just keen to learn new techniques, you may be able to alter your row gauge by changing your knitting technique. For some knitters, there may be a natural gauge difference between knitting flat (back and forth) and knitting in the round. For others, learning to wrap the yarn around the needles in a different direction -- for example, by switching from the combination knitting technique to the western style -- may do it. Alternatively, it may simply be a matter of the tension that's being exerted on the working yarn. You may be able to change your row gauge not by switching needle sizes, but by switching the way you wrap the working yarn around your fingers or hand to control the tension.

If you're knitting stranded colorwork (Fair Isle), you might be able to alter your gauge slightly by changing the way you're dealing with the non-working color on the wrong side of the fabric. If you normally leave floats of the unused color on the wrong side, try weaving the unused yarn on the wrong side instead.

... or adapt by matching the stitch gauge, then recalculating the number of rows you need to knit. Simply accept that you won't get both stitch gauge and row gauge to match the pattern, and deal with it accordingly. For most designs, it's preferable to match the stitch gauge, since garments are usually knit in the vertical direction (bottom-up or top-down), meaning that the garment width is defined by the number of stitches worked. In a bottom-up or top-down design, length is often a secondary consideration in the garment design and can be altered more easily than width.

In the easiest case, you're knitting a piece (or part of a piece) that's rectangular, such as the torso of a sweater, and the pattern gives instructions to knit to a specific length expressed in inches or centimetres. Calculating the number of rows to knit can be done in one step.

For example, let's say the pattern expects a row gauge of 7 rows per inch (2.5 cm) and you're knitting at 7.5 rows per inch (2.5 cm), and the instructions for the body of the sweater expect you to knit 14 inches (35 cm). To figure out how many rows you need to knit at your own gauge of 7.5 rows per inch, simply multiply the pattern-specified length by your personal row gauge: 7.5 rows per inch x 14 inches = 105 rows (round it up to 106 rows if it makes following the next step of the pattern easier).

In the next-to-easiest case, again you're knitting a piece that's rectangular, but the pattern gives instructions to knit to a specific row count rather than a measured length. That row count, of course, will be premised on the row gauge given in the pattern, which you're not matching, so one more calculation step will be involved.

Let's say the pattern calls for a row gauge of 6.25 rows per inch (2.5 cm), and the pattern reads "work 78 rows even", but your own row gauge is actually 5.75 rows per inch (2.5 cm). First, calculate the length of this part of the work, according to the pattern: 78 rows divided by 6.25 rows per inch yields 12.48 inches (31.7 cm). Then, using this length, figure out how many rows you need to knit: 12.48 inches x 5.75 rows per inch = 71.8 rows, so round up to 72 rows. In other words, since you're knitting fewer rows per inch than the pattern expects, you'll need to knit fewer rows to match the length required by the pattern.

Naturally, this process becomes more difficult when there is shaping that alters the width of the piece, such as waist shaping or armhole shaping. Typically this shaping requires a set number of decreases (or increases) spaced by a fixed number of rows; of course, if your row gauge is off, then your decreases and increases will not be spaced by the same absolute measurement. In these situations, you can either embark on a brute-force recalculation of all the instructions by sketching out the garment piece, calculating everything in terms of inches (or centimeters), then converting back to your real knitting gauge (if you did the sort of detailed preparation described here or had designed at least part of the garment yourself, as in this article, you'd be halfway done); or, you can use an easier approximation trick to make sure that your increases or decreases are spaced more or less the same way as in the original pattern.

First, for instructions that call for you to bind off a set amount of stitches at the beginning of each row a number of times, it's unlikely that there will be any need to alter the pattern instructions unless your row gauge is really, really off the pattern gauge (we're probably talking about more than 20% off the pattern's row gauge). Bind off instructions typically occur at the bottom of the armscye or at the shoulder, and typically don't take more than about 2 or 4 rows (in the case of armscye shaping) or 6 or 8 rows (in the case of shoulder shaping).

Similarly, for one-off shaping instructions, where increases or decreases are worked over one or two rows but not repeated, it's also unlikely that there will be a need to alter the pattern instructions. For example, when switching from the ribbing at the bottom of a sweater to the body pattern, the instructions may call for a number of increases spaced across the very next row. This step isn't repeated, so there's no need to make a row adjustment just for this increase row.

With instructions that call for increases or decreases reoccurring every X rows, the shaping takes place over a greater length of the garment, so adjusting the number of rows becomes more important. The general process will be:

• For this block of instructions, figure out how many rows the pattern instructions cover.
• Calculate the corresponding length (in inches or centimeters) according to the pattern.
• Convert this to the number of rows in your own row gauge and calculate how many more (or fewer) rows you'll need to knit.
• Sneak in (or subtract) these rows in the original instructions.

For example, you may have waist shaping that instructs you to "decrease 1 stitch each side on next row, and every following 8 rows 4 times" in a pattern gauge of 7 rows per inch (2.5 cm), when your own pattern gauge is 8 rows per inch (2.5 cm).

• For this block of instructions, figure out how many rows the pattern instructions cover: these instructions cover 1 row + 8 x 4 rows, or 33 rows total (there are five decrease rows).
• Calculate the corresponding length (in inches or centimeters) according to the pattern: according to the pattern gauge, this works out to 4.7 inches (12 cm).
• Convert this to the number of rows in your own row gauge and calculate how many more (or fewer) rows you'll need to knit: at your own gauge of 8 rows per inch, 4.7 inches works out to 37.7 rows (round this up to 38 rows); that's an additional five rows of knitting that you need to add in.
• Sneak in (or subtract) these rows in the original instructions: "sneak" these rows in by adding an extra row or two to the stretches of knitting that are worked evenly between decrease rows.

In this case, in an initial attempt you could try rewriting the instructions to read "decrease 1 stitch each side on next row, and every following 9 rows 4 times". That's not quite right, because you'll have added only four extra rows, not 5 as you've calculated. If you don't think the missing row will affect your overall length too much, you might leave it at that. If you want to make sure the extra row is included, then for just one of those repeats, work 10 rows rather than 9.

If your row gauge calls for more rows per inch than the original pattern, slip in extra rows between decreases or increases (the rows in darker red) so that you'll wind up decreasing or increasing the same number of stitches over an equivalent vertical distance. This technique of slipping in extra rows is analogous to the method you'd use to tweak a cross-stitch chart for use in intarsia.

Let's say, for the same example, that your row gauge is actually looser -- meaning, you're knitting fewer rows per inch than the pattern calls for. In that case, you'd need to subtract rows. Going back to the example where the waist shaping instructions read "decrease 1 stitch each side on next row, and every following 8 rows 4 times" in a pattern gauge of 7 rows per inch (2.5 cm), assume that your own row gauge is 6 rows per inch (2.5 cm):

• For this block of instructions, figure out how many rows the pattern instructions cover: these instructions cover 1 row + 8 x 4 rows, or 33 rows total (there are five decrease rows).
• Calculate the corresponding length (in inches or centimeters) according to the pattern: according to the pattern gauge, this works out to 4.7 inches (12 cm).
• Convert this to the number of rows in your own row gauge and calculate how many more (or fewer) rows you'll need to knit: at your own gauge of 6 rows per inch, 4.7 inches works out to 28.3 rows (round this down to 28 rows); that's five fewer rows of knitting that you need to work.
• Sneak in (or subtract) these rows in the original instructions: subtract these rows by omitting a row of knitting between decrease rows.

So, as a first try, you could try rewriting the instructions to read "decrease 1 stitch each side on next row, and every following seven rows 4 times". That will result in 29 rows of knitting, not the 28 you calculated. If that extra row doesn't matter to you, you're done; but if you want to subtract that extra row, then for just one of those repeats, work six rows rather than seven.

A couple of wrinkles: you may have realized that patterns are often engineered so that shaping stitches (increases and decreases) always occur on one side (right or wrong, public or private) of the garment. That's simply a matter of convenience for the pattern author, because some knitters find it easier to work these shaping stitches (especially if they're worked in mirror images) on the right side of the fabric. When you make this type of row gauge adjustment, you will likely respace your increases or decreases so that some of them have to be worked on the opposite side of the fabric. Also, If you're working with a stitch pattern that requires a set number of rows to complete a repeat, such as a vertical cable or color repeat, altering the number of rows to be knit may require a little more planning so that the repeat begins and/or ends at a pleasing location.

* Some people believe it is. Those are the people who spell it incorrectly, omitting the "u". Others who remember the "u" sometimes put it in the wrong place. Remember, "a" before "u" when they follow a "g", unless of course you are writing about guano or guarana. If you have this much trouble spelling "gauge," consider using the term "tension" instead.