Too Much Math
 

Right now I'm trying to figure out if I have enough fabric for a 2.5" bias binding. The quilt top is 64" square, so 64" X 4 is 256", plus two handwidths (16") for the final join and seams comes to 272".
The fabric I want to use has been cut into for border pieces so now the entire length of fabric is 31" wide, not the usual 44". That means my charts for binding requirements are out as well as the formula for dividing total binding inches by 11. These are all calculated on a 44" width fabric, right?
So now, I fold the fabric on a 45 degree angle and measure the length of that bias fold. It is 44". I have about 20 inches to go on the length of fabric which will yield 8 lengths of bias. 8 X 2.5"=20" (Plus the fabric triangles at each end that can be cobbled together if more is needed.) So I think I should get 352" of bias before seaming it together. 8 X 44" =352"
Does this sound right???
I've gotten myself all tangled up in the math sooo many times it's not even funny, I'd hate to whack up this beautiful deep purple fabric only to find I've miscalculated and come up short of what I need. Can anyone help with this or share a better way of figuring it out?

Math is not something I could help a horse fly with! When in doubt, when making a quilt, I ere to the larger point. Rather a larger quilt than one that comes out a little shy of what I wanted. When I lay a top on the floor if it doesn't look large enough I make it larger.

Sounds to me like the first paragraph is the length you need. 272" after it is all sewn together for the length. I don't know why you would want more than that.

I generally fake it until I make it and I always make too much binding. Better too much than not enough!

Here's a calculator that might help. It seems pretty easy and you already know all the measurements, it will let you put in the non-standard width.
http://www.quiltersparadiseesc.com/C...Calculator.php

What are the dimensions of the piece of fabric you have available for the binding?


The theoretical formula for figuring out if one has "enough" fabric:

Area of binding (length x width) needs to be less than area of fabric available (length x width).


Area of binding = width of binding x length of binding : 2.5 x 272 = 680 square inches

Area of fabric available = width of fabric x length of fabric : 31 inches x ______________?

680 divided by 31 = 21.94 inches. (Which would not be quite enough - in my experience.)


Remember to allow for "waste" - what is too small for the intended use and fabric "disappearance" - I am not sure where it goes, but if I am trying to get ten 3-inch cuts out of a 30 inch piece of fabric - I will only be able to get nine cuts.

I have the Robert Kaufman "Quilter's Little Helper" on my phone and use it frequently for quilty calculations. Math and I have never been friends. I would recommend it if you can get it. (It is free)

Just plugged in your measurements : Robert Kaufman says you need 266 inches of binding. This includes 10 inches "margin". Calls for a 30 inch square of fabric to make your bias binding.

Or you could just use Bear's formula! I am impressed!

wow, i've just been adding all four sides up and adding a bit maybe one more strip.

Wow!! Thank you! I had no idea there was an online calculator Iceblossom. According to that I have plenty. I forgot to include that my 31" wide piece is 51" long.
And thank you bearisgray, thats a good way to double check the math. I need ways to double check my math. Boy o boy do I need to double check the math. Instead of adding apples and oranges I could be including the pickles and end up way off track.
No cell phone service here suern3, but that's so impressive to be able to figure out right in the fabric store. We're short on fabric stores here, too, BTW.
The quilter's paradise page is bookmarked and theoretical formula duly noted in my notebook of important stuff.:thumbup:

If your quilt is square shape without curves, you don't need bias binding.

I have the same app as Sue and got the same calculations for bias binding.