After making a few sweaters using the "make your own pattern" pattern that Susan, from OSuzannah's Yarn, created. I decided to apply that same technique (simple arithmetic) to a shrug. I had this beautiful fuchsia yarn in my stash and thought it would make a lovely shrug. I am not a pattern maker. But I am going to try to explain my process in case anyone else would like to try this shrug.
To start I made a sample swatch from the yarn, using the size needles I wanted to use. I think the swatch was about 20 stitches by 20 rows. I then counted my stitches per inch and rows per inch from that swatch.
Second I measured my wrist, in inches. I took into account the amount of looseness I wanted around my wrist, since I didn't want the shrug really tight. I then measured my upper arm, by my under arm, also adding in any looseness I want. The underarm is where the sleeve will open up. My third measurement for now was the length of the sleeve, from wrist to underarm. Remember to take into account any cuff you want, and where you want the sleeve to fall, without the cuff attached.
Taking those three measurements multiply the wrist measurement by your stitches per inch. This gives you the number of stitches to cast on. Multiply the upper arm measurement by the stitches per inches. This gives you the number of stitches you want to end up with at the upper arm. Now take your sleeve length and multiply by your rows per inch and this gives you the number of rows, total, to go from wrist to upper arm. If you subtract your wrist stitch total from your upper arm stitch total you will have the number of stitches you will need to increase as you work up the arm. I increased two stitches every time I increased, so I divided the stitch increase number by two. Then I divided the number of sleeve rows by that last stitch increase number. This tells you how often you will increase. So you will increase two stitches every_______rows. For me it turned out that I increased two stitches every 6th row.
So start out with your cast on, wrist stitches. Join in the round, placing a marker where you joined (this is the start of the row). Knit in the round. Every time you get to an increase row, knit one stitch (after your marker) then knit front and back of the next stitch. Knit around until you have two stitches left in the row, then knit front and back in the next stitch and knit the last stitch. The great part about this pattern is that you can try it on. If the increases are too much you can stop increasing or you can add more if you would like it looser. Once you get to your underarm, stop knitting in the round.
Measure your back from underarm to underarm. Take this measurement and multiply by the rows per inch and you have how many rows you will go across your back. But again, try it on as you go to be sure it is how you want it to be. You will now proceed in stockinette stitch, knit a row and purl a row, until you are across the back and by your other underarm (no increases or decreases across the back).
Now start knitting in the round again, placing a marker where you joined to indicate the start of the row. And follow your pattern for the first arm in reverse. You will be decreasing down the second arm to the wrist. I took good notes as I increased so I could just reverse it down the other arm. Instead of increasing, on those rows, I knit one stitch then did a SSK, knit around until you have two stitches left in the row then k2tog and knit the last stitch. When I got to the wrist I bound off.*
For the ruffle pick up your wrist stitches. Join in the round, place marker at the join. Knit one row. Now knit front and back of every stitch, so you are doubling your stitches. Now knit three rows. Next row knit front and back of every stitch, again doubling your stitches. Now knit three rows and bind off. Do the same for the other cuff and the body. I did not count the stitches I picked up around the body. I just looked at it and picked up stitches evenly around. The ruffle for the body is the same pattern as for the cuff. If you can't just wing it for the body, you can measure the opening of the body, then multiply that measurement by your stitches per inch and that number is how many stitches you want to pick up evenly around the opening.
*One thing I would do differently next time. I would do a provisional cast on to start so that when I come back to add the ruffle I could pick up live stitches there and not have a seam. I would not bind off finishing the second sleeve I would just go right into the ruffle, again not having a seam. Although you can't see the seam, I just think it would be smoother.
I added a cable up the sleeve and across the back, you can see it in the picture. You can do that or not, or you can add any other pattern you like, or leave it plain. That is up to you.
I am sorry if this is hard to follow, as I said I am not a pattern designer. But if you have questions you can either comment here or e mail me at firstname.lastname@example.org and I will do my best to answer.