Sewing,  Tutorials

How Much Fabric Do I Need To Buy for Cutting Out Rectangles?

I’m trying something new on the blog.  I get a lot of questions from readers that I answer privately, but they are often very similar to each other.  I’m going to start answering questions that are not private in nature publicly on the blog so that everyone can learn from the answers.  Let’s share the wealth!

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Have a question?  Come ask me over on my contact page.

Today’s question comes from DJ:

HELP!!!! how much fabric would I need for 20 squares that measure 15″ x 16 1/2″?
THANK YOU

How Much Fabric Do I Need to Buy to Cut These Rectangles?

The way I calculate this is very similar to the method that I describe in my most popular blog post How to Calculate How Much Fabric You Need for a Simple Quilt.  The only difference here is that you are finding out how to fit how many rectangles instead of how many squares.

The first thing you’ll need to know is how wide your desired fabric is.  For example, it might be a 44″ wide quilting cotton or a 58″ or 60″ fashion fabric.  Usually the width is written on the end of the bolt when you’re purchasing it, but be sure to measure it as well because some fabric manufacturers may be wider or smaller than they say they are, or the unusable selvage edge may be larger than anticipated.  (Better safe than sorry!)

Once you know the width, you can determine how many rectangles you can fit in one width of your fabric.

Example One: 44″ Wide Fabric

  • Take the width (44″) and divide it by one of the dimensions of your rectangle. [44″ divided by 16.5″ = 2.66, rounding down to 2.] Therefore 2 rectangles fit in the width of the fabric.
  • Take the total number of desired rectangles [20] and divide it by how many rectangles fit in the width of the fabric [20 divided by 2 = 10 (rounding up if necessary)].  Therefore you need 10 columns of cut pieces.
  • Multiply the number of columns [10] by the remaining dimension of your rectangle [15″].  [10 multiplied by 15″ = 150″ inches.  Therefore you need to purchase 150″ inches worth of fabric, or 4.25 yards, to cut out the desired 20 fabric rectangles cut out at 15″ x 16.5″.

Example Two: 58″ Wide Fabric

  • Take the width (58″) and divide it by one of the dimensions of your rectangle. [58″ divided by 16.5″ = 3.52, rounding down to 3.] Therefore 3 rectangles fit in the width of the fabric.
  • Take the total number of desired rectangles [20] and divide it by how many rectangles fit in the width of the fabric [20 divided by 3 = 6.67 (rounding up to 7)].  Therefore you need 7 columns of cut pieces.
  • Multiply the number of columns [7] by the remaining dimension of your rectangle [15″].  [7 multiplied by 15″ = 105″ inches.  Therefore you need to purchase 105″ inches worth of fabric, or 3 yards, to cut out the desired 20 fabric rectangles cut out at 15″ x 16.5″.

Keep In Mind:

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When working with rectangles, it may be more economical to cut the rectangles rotated the other way around so that you can get more rectangles within the width of your fabric.  For example, if you have a 45″ wide fabric and you want to cut a 15″ x 16.5″ rectangle, you can fit 3 rectangles if you stack the 15″ side of the rectangles in the width versus only 2 rectangles if you stacked them the 16.5″ direction.  When doing the math, you can reverse the two dimensions to see which one gives the more economical result.

Cutting Process: 

After you buy your fabric, you’ll need to cut the fabric in the same way that you calculated the fabric otherwise you won’t fit your rectangles all in.  The first thing you’ll want to do is cut all the columns.  In the case of this example, the columns are all 15″ wide.  Then after the columns are cut, cut the columns up to have the number of rectangles you could fit in each row.  For each column, there will be a little fabric leftover.  Here is a sample cutting diagram for example one:

Remember: measure twice, cut once! Good luck!

Have a question?  Come ask me over on my contact page!

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2 Comments

  • Sherry lavalley

    How much material would i need to make a king size quilt yardage or how many squares if squares are 45×24

    • Angela Welsh

      Hi Sherry,
      My suggestion would be to draw a diagram representing your 78″ x 80″ (king size quilt) dimensions. Are the 45×24 rectangles in inches, and are those dimensions with or without seam allowance? They may not fit evenly into a king size quilt.
      Divide up the 78″ x 80″ rectangle that you drew into sub rectangles. These will represent each of your fabric squares.
      Once you draw your diagram, you’ll be able to see how many rectangles you’ll need in total, then you can use the math I describe in this post to calculate how much you need.

      You may also want to reference my post
      “How to Calculate How Much Fabric You Need for a Simple Quilt” if you don’t know what I mean by drawing a diagram. http://craftcore.ca/2012-11-23-how-to-calculate-how-much-fabric-you-need-for-a-simple-quilt/ You can colour in each square/rectangle to represent each fabric you want to use.

      Hope that helps!

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