How to Calculate How Much Fabric You Need for a Project

Are you ready to start a sewing project, but you’re never sure how much fabric you need? I’d love to tell you that there’s a one-size-fits-all type of formula, but your calculation depends on what you’re looking to make.

If you want to calculate fabric yardage for upholstery projects, please try using our visual calculator or fabric yardage calculator to understand how many yards of upholstery you will need. This tool will provide easy yardage estimates for total yardage, so you have enough fabric.

Our fabric calculator will also advise ordering extra yardage and extra upholstery when deciding how many yards you need if you are dealing with large patterns or if your fabric pieces are not the same size. For large pieces, pattern pieces, you may need multiple pieces depending on the size.

Calculating the amount of fabric you’ll need for a project really depends on the project. A winter coat’s yardage is calculated differently than the yardage for a throw blanket. Let’s see how to calculate the amount of upholstery needed for some common home decor items.

How to Calculate How Much Fabric You Need for a Project:


When measuring to see how much upholstery you need to make your own curtains, you first need to determine if the fitting is inside or outside the window frame. For curtains that go inside the frame:

  • Take a measurement along the width of the window within the casing, moving from one side to the other. 

  • This number should then be multiplied by anywhere from 1.5 to 2.5, depending on how full you want the ultimate result.

  • Next, take a measurement all the way down to the sill from the top of the casement. 

  • Make sure to leave room for hemming and a header. 

  • You will need to add an additional 6 inches to the length to accommodate a header that is 3 inches in height. 

  • Similarly, an allowance of four inches is required for a hem that is one inch.

The process is a bit more complicated for curtains outside the window frame. Also, please be aware of the width of the fabric you are using for accurate yardage when calculating the fabric needed.

Step #1: Measure the Width

Take a measurement across the outside of your window from one edge to the other to determine its width. After that, take measurements of the curtain pole. Your drapes’ width must be proportional to the length of the curtain pole. You will need to add an additional six inches to the window width if the pole goes beyond the window frame by three inches on each side. When using pieces that are not the same size, please be aware of the fabric width to avoid unnecessary seams.

It is recommended that the width measurement of the curtains be at least twice as wide as the width of the window to get the desired fullness. Aiming for a window that is 2.5 times larger than the one you actually have gives you room for both extra volume and faults. If you intend to use two panels, divide the total measurement in half. Estimate extra for seam allowances and use sturdy upholstery.

Step #2: Measure the Drop

You should measure the length of your curtains from the pole all the way down to either the floor or the windowsill. This phase will be much simpler if the pole has already been set up. Go from the location where you want the pole to be positioned if you haven’t already fitted it.

Make a decision regarding the size of the header you wish to use. If you choose to use a header that is three inches tall, you will need to extend the length of your curtain by an additional six inches. This will ensure that there is sufficient fabric on the reverse side to produce a robust band, which may then serve as an anchor point if you plan on having rings or tabs.

Step #3: Consider the Extras

Include some additional fabric to cover the seams and hems. The bottom hemline of your garment should be at least six inches long. Add this number to the total length of your curtains so they are the correct length.

How Much Fabric You Need for Throw Pillows

Choosing the appropriate quantity of cloth is just as crucial as selecting the appropriate color and pattern for the material. If you buy too little fabric, you end up with scraps that can’t be used, and if you buy too much, you’re just wasting money. 

Step #1: Take the Measurements

Utilizing a flexible tape measure, take the pillow’s measurements for both its length and width. Be sure to leave a nice seam allowance of half an inch all the way around the pillow

To properly cover a pillow that is 14 inches square, you will need two pieces of fabric that are 15 inches square each. Half a yard of fabric would be the appropriate amount of material for a pillow of these dimensions. 

You’ll get an amount equal to half a yard in length and whichever width the bolt is. You may be able to produce two pillows from one buy of fabric, but this will depend on the size of the pillow as well as the width of the bolt.

Step #2: Consider the Fabric Width

Fabric is typically sold on bolts, and the width of the bolt determines its size. The width increases from 36 to 45 inches, 54 inches, and finally, 60 inches. The smallest width is 36 inches. 

The fabric is double-layered and wrapped in durable cardboard by the manufacturer before being packaged for sale. Cloth for upholstery is typically available in wider bolts measuring 72 or 118 inches and consists of a single layer of fabric rather than a double layer. Fabric shops will cut the required amount of fabric from the bolt based on the dimensions you provide. 

Always refer to the measurement you request as a yard or a portion of a yard when you ask for a specific length. Instead of inches, you should request that your fabric be cut into eighths, quarters, half yards, or whole yards.

How Much Fabric You Need for Slipcovers

The tricky part about slipcovers is that the amount of fabric you need depends on the size of the furniture piece you’re looking to cover, for example, in chair upholstery.

Here are some general guidelines for textiles that are plain colors; patterns may require more to match the individual components up properly. Take note that the longitudinal measurement used to determine the price of the fabric is called a yard. 

Before making a purchase, you must check the width of the fabric bolts at the craft store to ensure they are the right size for your project. The widths typically range from 32 to 60 inches, with 45 and 60 inches being the most typical sizes. 

For instance, you’ll need about 17 yards to make a slipcover for a 4-cushion couch but 22 yards for a 6-cushion sofa. 


How do you calculate fabric usage?

The easiest formula to calculate fabric usage is to measure all the parts for the reference product and add the lengths and the width for all. Of course, the formula varies on what it is you’re looking to make. It’s easier to calculate how much fabric you need for a 50 x 60 throw blanket but not that easy when it comes to a dress, for example. The fabric width is very important for your fabric yardage.

How do you calculate yardage for upholstery?

If you’re making some upholstery with a pattern repeat and want to calculate the yardage, add the vertical and horizontal measurements plus an additional percentage. 

Bottom Line

Thankfully, the internet is an oasis of knowledge. Regardless of what you want to sew, you’ll find information and calculators that will tell you how much fabric you need for this and that. All you need is a sewing machine, some free time, and the best fabrics from our site!

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