## Monday, January 14, 2008

### Geek du chêne

While I was working on the Okie Dokie doily yesterday I began to wonder how far along I was.
I mean I could look at the pattern and see how many rows were left.
But those rows were getting bigger and bigger, and I wanted to know exactly what percentage I had left.

So I turned to the resident geek (aka my husband) and asked him how I would go about figuring it out. In no time he had a simple little formula for me. This formula works if you are knitting a center out circular or rectangular shawl/blanket, it works if you are knitting a tip up triangular shawl, and it works if you are knitting a center neck out triangular shawl, essentially, if you start with a tiny number of stitches, and end with a huge number of stitches, this formula will work. (This does not count Faroese style shawls, there's funky shaping involved that the formula doesn't account for.)

(Total Rows in project)²

all that x 100 = the percentage finished.

So how far along am I with Okie dokie?

55² ÷ 123²=.199

.119 x 100 = 19.9%

yeah... I need to get knitting.

{ETA}
If you want to be extra geeky with this, try typing it into Google.

((55^2) / (123^2)) x 100

trek said...

You could also calculate the area of the project knit so far and the area of the final project. I did that with my triangular shawl and it was very accurate.

And you don't have to use rows and stitches, you can use motif repeats and pattern repeats. See?

½(base)(height)=area

½(# medallions)(pattern repeats)=area

Abigail said...

"You could also calculate the area of the project knit so far and the area of the final project. I did that with my triangular shawl and it was very accurate."

that is essentially what this formula does, it's just really simplified.

the original formula that Bill wrote up was for my okie dokie, which is round.

area of a circle = pi x R^2

so for okie dokie it was area already knit divided by area total to get the percentage,

pi x r(finished)^2 / pi x r(total)^2

and to simplify the pi's canceled each other out. this is good, because a similar formula for squares and triangles simplifies out to be exactly the same.

and instead of calculating radius in inches, the formula uses rows (but like you said, can use pattern repeats) because those are readily available, and most lace, the final area is unknown until it is finished.

Sara said...

Arithmetic makes me whimper. However, this is still really cool. ;)