How to figure size if using a different hook

[dgatlin51]

I would like to know how to figure out what the size difference will be if you use a different size hook and yarn? Example: I am working on a blanket that calls for #4 weight yarn (like RH super saver) and a J hook but would like to use a thinner #4 yarn (like Caron Simply soft) and an H or I hook.

[magiccrochetfan]

Hi, welcome to the ville!

 

You need to make a swatch and count the stitches and rows in an area, like a 6-8 inch square.

[Granny Square]

There is no magic formula, because there are so many yarns and so many crocheter's individual tensions.  The best thing to do is do a swatch and do a bit of math.  

 

Just an observation, but RHSS is not THAT much thicker than CSS.  I personally wouldn't change the hook called for on a blanket, but I would check the gauge for a garment (even if using the called-for yarn).

 

Are you following a pattern, or just winging it?  If you are just winging the blanket and using a plain stitch or a stitch pattern that says something like 'multiple of x+y', and want to get close to a specific width measurement, just make a chain of that width without counting for a plain stitch, or in multiples if using a stitch pattern.  

 

Do you want it to be the same size as the pattern says it will be?  If the pattern says to chain x, but doesn't have a note to 'add multiples of y if you want it wider', you could make a chain a few inches longer than the width you want, and work across in the stitch pattern and stop when you get to the width you want.  Later, you can pick out the extra chain stitches and weave in the end, it won't unravel from the knot end.

 

To answer your question about size difference, you will have to do a swatch in the blankets' stitch pattern.  Gauge swatches are typically x stitches for a 4" or 10mm square.  If you are using smaller hook and yarn, you'll have a smaller square.  Measure it, to the fraction of an inch.  Calculate the width of 1 stitch.  Then multiply that x the number of stitches across of the pattern - that will tell how how much smaller your piece will be, compared to the pattern.

 

Example, let's say the pattern is 48 inches across, the gauge is 4 stitches per inch, and is 192 stitches across. Each stitch is .25 inches.  (0.25 x 192=48")

Let's say our gauge comes out to 4.25 stitches per inch, so each stitch is .235 inches across.  .235 x 192 is 45.12 inches across.

 

Sigh, Magic, I knew that was going to happen as I was working on the math!  Maybe I'm just too long-winded

 

Edit to the OP, Magiccrochetfan is absolutely right that you should make a swatch larger than 4" because it's more accurate (the stitches on the edges can throw the calculations off a bit).  And if you were making a garment, this is really important.  But for a blanket...it doesn't matter so much if you're a wee bit off.

[magiccrochetfan]

Haha GrannySquare, i left my first post to try to find an article with some of the info on the math, but i was not able to find one that really explains it. Came back here to try to add some info, and there's your (not long winded at all) post! Yay for you!

 

Oh, i will say that i have found SS to be noticeably lighter than RHSS so i would probably use a smaller hook for it.