How do I figure how much yarn is needed for a project?

[Narria]

I rarely use patterns for things I make on a regular basis, unless I am looking for a particular design or stitch. I can usually figure out how much yarn I need no problem. However, my neighbor asked if I could make her a blanket for her bed... a King sized bed, with a tight stitch, not bulky yarn. I have made blankets for single beds in the past using 12X12 granny squares stitched together, but they were not tight stitches and I don't want to do granny squares. I would like to make the blanket big enough to drape over the sides at least 6-7 inches and the foot 12 inches. I found that the bed is 6.6' long by 6.3' wide which I believe, rounded up is about 80" x 76" with the additional inches for draping the blanket will have to be about 92" x 90". So how do I figure it out? I was thinking I have to first figure out the square footage then determine how many square feet I can get from a skein. Is that the correct way? I do know that different types of yarns go further then others of the same yardage based on stitch and all that, but I have never had to figure out just how much for something this big. I really want to make sure I have enough yarn for the project. I will err on the side of safty and buy a bit more then I need, but I first need to get some kind of idea to work with.

Thanks for any adivce you have to give.

[BarbySue]

I too, am interested to see what responses are made to this post. I either buy way too much yarn or not near enough. It would be nice to get a more educated guess and be closer to the mark.

[Pixieglitter]

If you buy too much, which is what I recommend, you can always return the leftovers you haven't used, with your receipt. I've found stores (like Hobby Lobby) are more than willing to accept returns on unused yarn as long as you have the receipt. Are you wanting to make the bed cover all in one color? If you change out colors it might be a little easier to figure out how much you should buy.

I've made several huge afghans for my boys who are both very tall, they're like 6'3" tall and I wanted them to be able to wrap up in them. I like to use a ripple pattern with different coordinating colors, in DC which works up quickly and is very easy for me to "eyeball" how large I want it to be. I usually buy about 16 skeins of 7 ounce worsted weight yarn in a few different colors. It might take more like 18-20 skeins of 7 oz of yarn to fit a king size bed with a drape. I always use 100% acrylic because you can throw it in the washer and dryer and it comes out looking like new.

I'm interested in reading what others have to say about the amount of yarn you'll need.

Shelley

[E. J. Horn]

Would you (and this is just my thought) multiply the wxl, to get the total sq. in. Then divide by 36 to get the yardage, Then figure the gauge of the pattern, the rest is depending on the yarn. I sure don't know what I am talking about have just been re-learning crochet for a few weeks now so I am not the person to know. Hope this helps. ev

[Barbara G.]

Here are some great resources when figuring how much yarn is needed for a crochet project:

How much yarn do I need? | FreshStitches

Estimating How Much Yarn to Buy - For Dummies

Yarn Calculator - The Crochet Crowd