Having enough quilt fabric on-hand to finish a quilt top is important to the serious quilter. What could be more aggravating than getting nearly finished with your quilt only to find out that you are out of quilt fabric?  To make matters worse, many quilters keep a stock of fabric on hand.  Should the fabric you are running short on come from that stash, the chances are good that you may never find the same fabric/dye lot again.  If you take the time out to lay out your quilt beforehand and measure carefully, then you will know exactly how much quilt fabric you will need for your project. This can keep your project on track and save you from pulling your hair out in frustration. 

Follow these steps to figure out how much quilt fabric you actually need:

• Draw out your pattern onto graph paper.  For those patterns where you plan to repeat a block or blocks in your quilt, you will only need to represent each block one time.  Take note of the number of each individual block you will need for the quilt.  Each square represented on your graph paper must be a unit.  Make a note of the length and width of your quilt. 
• Create a key or map for the pieces of your quilt top.  Include any borders or sashes.  Note the finished length and width next to each piece.  Remember to leave a 1/4th” allowance for a seam on either side of the block. This is the cutting size. 
• Each block should be assigned a quilt fabric pattern swatch or color. 
• Add up the total number of blocks or pieces that you need in each fabric pattern or color.  You will need this many pieces in order to have enough for each type of fabric that you are using. 
• Most fabric bolts are 42” wide.  For this reason, when measuring, divide the length by 40 to just be on the safe side of the calculation. 
• Next, divide the total sum of needed pieces by the total sum of pieces that can be taken from the bolt.  You will need this many columns for that number of pieces.  Multiply the sum total by the cutting piece width. This figure will be the total number of inches that you need.  For instance, if your quilt needs forty pieces of 4”x8” rectangle, then 10 rectangles should be cut from each width of the bolt.  The number of columns needed will be four, and the total length of quilt fabric that is needed is thirty-two inches. 
• Keep in mind that some quilt fabric will have to be wasted on particular designs. 
• Allow for making a mistake or two.  Once you have your amount of quilt fabric calculated, you should have some extra fabric on-hand to allow for mistakes or for those instances when you might incorrectly cut your fabric. 
• There are some tools that you might use for calculating the amount of quilt fabric that you need.  Quilting reference books and fabric calculators can go a long way towards making sure that you have the right amount of fabric for your quilting project.