Help creating my own blanket pattern, x-post

I’m trying to write a pattern to make a blanket, 6 feet square, out of a worsted weight yarn, 110 yards per 50 gram ball, guage 4.5-5 sttiches per inch. I have no idea how to figure out how much yarn to buy, I know I need a lot. What is more, I want to knit it in a specific pattern, in sections measuring 30x30 inches, 24x30 inches (2 sections), 24x24 inches, 30x18 inches (2 sections), 24x18 inches (2 sections), and 18x 18 inches.

Help?

I would think that making a swatch in the stitch pattern you’re planning on. Then I would take that apart and measure yardage used and multiply out. I always just buy extra for afghans and then just keep going until I’m almost out of yarn and then finish off. I like oversized afghans anyway.

You should be able to get a good estimate by knitting the sample like Plantgoddess suggests and then weighing it. Weigh a skein and compare.

Another thing I do is: Using pins or something that will cling to my yarn, actually place a pin every yard for about 3-4 yards, then knit a row and subtract from what is left. It will not be accurate but will give you some idea how many yards make a row. You can even knit a swatch 20 sts by 20 rows, or whatever numbers would be easy for you to remember, rip it out and measure.