On Tuesday, I shared the requested information for matching fabric patterns when sewing seams. Computing yardage for fabric with a pattern repeat is another topic a few readers have asked me to provide.
In an attempt to be clear, I’ll explain the formula in detail and define some terms. At the end of this post, I’m sharing a Pinterest pinnable formula chart so you can refer to it straight from your smart phone when you need it. If you don’t have a smart phone, I’ve provided a PDF file that you can save and/or print. I’ll explain further when we get to the chart.
This print has a rather small repeat – only 6-1/4″. That small repeat affects the yardage needed for a project only a small amount, and many times people simply purchase a little extra fabric – and guess at it. That can work for a small repeat…sometimes. But, I wouldn’t recommend it.
When you calculate yardage for pattern repeats, it works the same for any size repeat. Once you get the concept in your head, it makes sense and becomes easy to remember – with a little memory jogger, like the chart.
Remember in math class how well you did on tests when you understood a concept? Memorization doesn’t work without understanding what (and why) to plug into a formula. Please read this post (either now or later – or both) to grasp the concepts so you’ll understand the chart when you need to use it.
I realize that many of you don’t need this post right this very minute. At some point, you’ll be searching for this information – to read in full and grasp the concept so you can compute your fabric needs (hence, the chart). I’m providing all the details in this post.
Before we begin, here are a few ifs, ands, and buts:
For calculating fabric needed for upholstery, we must consider the horizontal and vertical repeats. Since I’m not an upholsterer, I found a wonderful site for calculating that yardage HERE.
When making most window treatments, you need to consider only the vertical repeat. There is also what we call “railroaded” fabric, where the pattern runs length-wise down the run of the bolt. The print runs “sideways” from the normal way. Do NOT use a railroaded fabric for panels unless you like the direction of the print hanging length-wise, which is actually running sideways.
Treatments like this design require using a pattern. The pattern instructions should give you the details you need to compute the yardage needed for fabrics with a repeat.
Now that we’ve covered some “ifs, ands, and buts”, let’s move on to our topic of calculating repeats and fabric needs.
Measuring the Vertical Repeat
I’m bringing this fabric out of the archives. You’ve seen it all over my window treatment tutorials. To measure the repeat, place your tape measure at a point on the pattern and extend the tape to the next exact spot. My archive fabric has a rather large repeat at 26-5/8″.
Since 5/8″ doesn’t compute well, round it down to 1/2″, which converts to 26.5″, or round it up to the next inch. Let’s round up to 27″ for our panel computations. We may come out with a few inches extra fabric when buying many yards for panels, but you’d rather be a teensy bit over than run short (argh!).
Yardage for Panels
Let’s say we’re making 90″ panels. With 8″ added at each end for the hem and header, that’s 106″ total needed for one panel (or panel width if making very wide panels – double or triple widths).
90″ + 16″ = 106″ cut length
106″ length needed ÷ 27″ repeat = 3.9259…or 4 full repeats needed
There’s no way to use a partial repeat, so round the 3.9 repeats to 4 and multiply by 27″. Purchase 4 complete repeats per panel or panel width.
4 repeats x 27″ repeat measurement = 108″ needed per panel (width)
Now, we don’t go to the counter and ask for them to cut 108″ of fabric, so divide the 108″ by 36″, and you’ll ask for 3 yards. Well, it rarely happens that you come out with an even number of yards here, but we got lucky with our example measurements.
Multiply the yardage for one panel by the number of panels you’re making (or the number of widths for the project). You’ll want one entire cut of fabric, not a separate cut for each panel or width.
3 yards per panel x 4 panels = 12 yards
If the calculation comes out not being a whole number, I round up to the next yard. (Sometimes I purchase one or two extra repeats.) This gives me extra fabric to allow for miss-cuts (oops!) or for making pillows. I included this rounding notation on the yardage chart to remind you, but it’s not required.
You want all your panels to be identical. Cut each panel at the same location on the repeat, all at the required length (mine being 106″).
Yardage for Valances
Computations are the same when computing yardage for valances, but it may seem different due to the way they are made.
When making valances, you have several widths of fabric sewn together, forming a long strip of fabric.
Let’s use a 16″ repeat for this example, and let’s say our finished valance will be 18″ from header to hem, using 3 fabric widths. We’ll add 6″ total for header and hem.
18″ finished height + 6″ (header and hem combined) = 24″ cuts per width of fabric
24″ ÷ 16″ repeat measurement = 1.5, which we round to 2 full repeats per width
2 repeats x 16″ = 32″ per width
32″ x 3 widths = 96″
96″ ÷ 36″ = 2.66 yards, which is technically 2-2/3 yards
If you round up the yardage, like I do, you would actually purchase 3 yards.
Not to complicate things further but to provide the information you might need at some point, let’s look at the valance above with our 27″ repeat fabric. How do you handle a cut measurement that is smaller than the repeat?
27″ repeat for 24″ cut length = one full repeat per width
We would simply trim away 3 inches at the upper or lower edge of the repeat. (Remember to be consistent and cut each width the same.)
27″ x 3 widths = 81″ needed for treatment ÷ 36″ = 2.25, or 2-1/4 yards (which I convert to 3 yards)
The Formula in Detail for Review
Cut length needed (inches) ÷ repeat measurement (inches) = # repeats needed per width (rounded up to nearest whole number)
x repeat measurement = total length to purchase per width x number of widths for treatment ÷ 36″ = yardage to purchase (rounded up to nearest whole yard
To Pin this formula chart, click the Pin it button at the top of the page under the post title. Your computer screen will be filled with all the pictures from this page, so click this image and pin it to one of your boards. (Hey, someone needs to invent a phone app for computing fabric yardage! Hmm…)
If you don’t have a smart phone, click the picture, and it will take you to a PDF page, where you can print the image and/or save to a file.
Of course, you could always ask the employees at your fabric store to calculate the yardage for you – if you trust them to figure it right. After reading this post, you’ll be prepared with the necessary measurements they’ll need for making the calculations.
If you have any questions about calculating yardage for fabric with a repeat, please talk to me in the comments section. I’ve tried to be clear and simplify this process as much as possible, so I want to know. Did I succeed, or do I need to try a different approach later?