Gauge Schmauge - Is It Close Enough?

I spend a good chunk of my days answering questions and giving advice (knitting advice, that is), and sometimes people aren’t thrilled with my answers. Nothing makes people sigh, grumble, or roll their eyes more than when I mention gauge. But really…I’m going to say it again…gauge is important, especially if you want what you’re making to actually fit.

Being the gauge-nag that I am, I thought I’d wow you with my mathematical expertise to show you an example of why it’s so important, because really, it boils down to simple math. (Disclaimer: In truth, I have NO level of mathematical expertise. It would be more appropriate to call it my “mathematical bumbling skills”.)

You look at your pattern, and you decide to knit the large size with a finished chest measurement of 46”, and the gauge is 4 stitches per inch (or 16 stitches in 4” – it's the same thing). You knit up a lovely swatch (we’ll talk more about swatches next time), count your stitches, and you come up with 4.25 stitches per inch (or 17 stitches in 4”). You declare, “Close enough!” Then you cast on and start your sweater.

But is it really close enough? Let’s run the math:

Looking at the pattern, we see that the chest of your 46” sweater contains 184 stitches. Yup, that makes sense:

184 (stitches) ÷ 4 (stitches per inch) = 46 (inches), just like the pattern says.  184 ÷ 4 = 46

But at the “close enough” gauge of 4.25 stitches per inch, it works out like this:

184 (stitches) ÷ 4.25 (stitches per inch) = 43.29 (inches).

So, that little quarter of a stitch impacted the finished size of your sweater by almost 3.5 inches. And that’s just being off a small fraction of a stitch per inch. What if you count 4.5 stitches per inch in your swatch? You’d end up with a 41” sweater instead of 46”. And what if you got 3½ stitches per inch? You’d be drowning in your almost 53” sweater. Wow. See? Gauge matters.

I know I’m throwing a lot of numbers at you, and your eyes are probably glazing over. Here’s how it shakes out in a nice, neat little table:

If you have 184 stitches around the chest:

Gauge (stitches per inch) Finished chest size
3 1/2 52.57"
3 3/4 49.07"
4 46"
4 1/4 43.29"
4.5 40.89"
5 36.8"

See how the same number is stitches can make your sweater measure anywhere from almost 37” to over 52”? 

It’s a pretty simple equation to calculate. Just remember: Total stitches* ÷ Gauge = Finished Size.

So, next time you think your gauge is close enough, run the math. Maybe it is, but maybe it isn’t.

*The Fine Print:  I use the total stitches in the chest of the garment. Keep in mind: sometimes the sweater might start out with fewer stitches for the ribbing or there may be waist shaping. Also, if there’s a button band added at the end, it may add an additional inch or two. Be sure to calculate using the number of stitches at the widest point – usually across the chest. If the sweater is knit in pieces, be sure to add up the total number of stitches (right front + left front + back stitches).

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