Crochet Math

Hi all.

So I'm in a finance class right now and getting lots of math practice in.  Then I realized... there is actually a lot of math involved in crocheting... and since I am not a math lover... it took me many years of crocheting before I figured it out.

These are tricks you math lovers might know already.  BUT - if you are like me and math rarely consumes your mind, these tricks might come in handy.

FIRST ---  some math to figure out yardage.
It can be helpful to keep your yarn wrappers if you don't remember the kind of yarn you are using, and this is why...  there is some kind of useful information on them.  Here is an example:

The pieces of info you will need are Ball Weight (2.5 ounces) and Length (120 yards).  Now you just need a scale (I use a food scale) and you can figure out about how much yarn you have left in a skein OR how much yarn you used for a project.

So say you weigh your project and it weighs 5 ounces.  (This one is easy)

120 yards  x  ?????yards  =    
2.5 ounces   5 ounces

So do some cross multiplication.  120 x5 = 600   Then 600/2.5 = 240 yards.  You used 240 yards.

Here is a harder one.  Your project weighs 13 ounces.

120 yards    x    ?????yards  =
2.5 ounces      13 ounces

120 x 13 = 1,560   Then 1,560/2.5 =  ABOUT 624 yards.  (Allow for some rounding in the weight unless you have a really fantastic scale!)

SECOND - some math to figure out size.
To figure out the size of something you need a really accurate gauge.  So when you read a pattern and the gauge says:  13 stitches and 16 rows of sc = 4 inches with an H hook, you need to make a swatch with an H hook and your chosen yarn and make sure 13 stitches of single crochet across and 16 rows up really equals 4 inches.  If it is bigger than 4 inches, switch to a smaller hook like a G.  If it is smaller than 4 inches switch to a larger hook like an I.  For this math to work, your gauge has to work.

OK so now, say you are making a piece that is  55 stitches.  You can figure out how many inches across that will be.   Because you are dealing with stitches across, you will use 13 as your number.

4 inches       x     ????inches  =  
13 stitches            55stitches

4 x 55 = 220    Then,  220/13 = 16.9  or about 17 inches.  So when you make the 55 stitches across it will be about 17 inches.

The same works if you are dealing with rows.  So now say you are making a piece with the same gauge that has 80 rows in its pattern.  You can figure out how many inches long it will be.  Because you are dealing with rows, you will use 16 as your number.

4 inches        x     ????? inches   =
16 rows               80 rows

4x80 = 320  Then, 320/16 = 20 inches.  So when you make 80 rows with this gauge it will be about 20 inches.


WOOHOO!  Good job with your math!  These are two tricks that are so incredibly useful as a stitcher, and it took me an long time to realize them... hopefully they will help you out in all your stitching adventures!!!  (And this works with knitting too!)