Is there a formula for calculating thread/yarn needed by stitch pattern???

[Gran]

I've been wanting a formula that would tell me, by stitch, how to calculate the amount of thread/yarn, by size, the amount/length needed for the end size of the project.

 

Ex.: For size 20 thread, alternating single and double stitches, (not unusually tight or loose), to arrive at the length of thread needed for a 40" x 72" shawl or blanket, the formula is "x".

 

Found the following and thought there must be some way to adapt it to crocheting:

 

www.amefird.com/estimating_consumption.htm

 

Variables I've thought of to plug into formula:

- thread/yarn size

- end size of project

- stitch pattern

- going up or down hook sizes from recommended norms

 

Any of you math wizards online and interested? Thanks.

[SaxDragon]

hmmm... interesting. It would save a lot of time.

 

I do it the hard way - make a swatch, then either weigh it or just plain unravel it and measure it. Then multiply it out for the size I want. Much less frustrating than algebra, but time consuming :-)

 

I once saw the formula for figuring out how many clusters were in each round of a granny sqaure - actually it wasn't for crochet, but it did the same kind of thing by plugging in how many increased by how many times (rows) of something (in chemistry I think) in a succession. Geez, that was like 20 years ago ... I feel old now LOL

[earthwhisper]

I have read your post several times and am trying to grasp what you mean. Are you going off of a pattern or are you designing something and want to know how much you will need?

 

Would this work?

 

Multiply the number of stitches in a row by the number of stitches in a column. This would equal your total stitch count.

 

Then, weigh the item you are measuring. Divide the total weight by the # of stitches and that will give you weight per stitch.

 

If you knew that for every ___# g of yarn you had____yards of yarn than you might be able to convert it to length. For instance, if you used 100g balls of yarn that were 100 yards, you could convert how much weight per stitch to how many yards per stitch.

 

Is this they type of thing you are looking for? It looks complicated. I will be curious to know why you want to calculate such a small amount.

[natalie058]

I'm just not sure that it's actually possible to make a universal usage formula.

 

First of all, everone stitches differently. Your dc probabaly doesn't use exactly as much yarn as my dc or her dc; so who's dc is the "universal" dc?

 

Secondly, factoring in the weight of the yarn [ww, dk, etc] is just not exact enough - we all know how subjective those classifications are.

 

And, using a yd/gm formula to calculate weight wouldn't cut it either, because all fibers do not have the same mass.

 

Wendy, what you said was very interesting though, and I really do think it would work on a person to person basis - especially for more experienced crocheters who will make their stitches uniformly most of the time. It would take some initial time to crochet the swatches, and record the measurements, but in the future I think you could use those measurements to estimate yarn usage with reasonably acuurate results.

 

However, if I were to use your measurements to estimate, I think the chances would be high that the results would be wrong.

 

But now that I think further on it, I'm not certain how your calculations would account for a change in fiber, either...

 

Really, I'm just not sure there are factors ever constant enough to measure to create a formula that would work for *everyone.*

[Gran]

Could there be a formula with one factor constant, i.e., the crocheter? Given uniform stitches by that crocheter, each crocheter could have a set of formulae per stitch pattern. That is what I found so intriguing about formulae for estimating consumption on the amefird site.

[natalie058]

If I'm not mistaken, though, the sewing calculations assume that one is using a sewing machine, thereby producing a constant stitch. Also, sewing thread sizes are far more standardized than yarn weights.

 

Wendy's thoughts are practical assuming one uses the same fiber to measure with as for the final product... one crocheter may know for certain that everytime she makes 10 dcs in size 10 cotton thread, she uses x yds. Which is basically what SaxDragon described, without the mathematical headache.

 

I think what is boils down to, again and again and again, is swatching. Each crocheter is going to get a different result with different yarns.

[Gran]

Thanks for the ideas. I, too, think swatching, measuring and weighing are a part of crocheting. AND, I would like to come up with some formulae for myself.

My question is really about the how, please, to calculate.

 

So, if the formulae should appear, I'd be very thrilled to see them.

[crochetmama]

Here's my 2 cents (and I'm definitely NOT a mathmetician!):

 

Why not start keeping a log of your projects and how much yarn/thread you used. That would take into consideration your style of stitching and that particular yarn/thread in that particular type of pattern. You could differentiate between a lacy, DCs, dense (all sc), or aran (dense with clusters) type of projects. I've seen several crocheters (and knitters) who keep detailed logs on line which detail the pattern name, the type of stitches, the yarn name, the size of the project and/or modifications, and the amount of yarn used. You could also designate if it was a chunky, bulky, fingering, #10 thread, etc. I have some things I make frequently, and I have a pretty good idea of how much yarn or thread to get for that project. Also knowing that information helps me to "guestimate" on similar projects with the same yarn/thread type. For example, since you like to do things without a pattern, your log could say, Baby blanket (size 40" x 40") I made for so-and-so in the _____ yarn was X of the 3.5-oz skeins. If you kept your log on line, then you could keep pictures too to remind you which design you used (and share with us!)

 

If you do ever find a good universal formula, let us know too!

 

(P.S. I'm in awe of Wendy and Natalie--Those ladies are SMART!!)