Sunday, April 10, 2016

Calculating Ruffle Yardage

Early on in my sewing I used to guestimate how much yardage I needed to make ruffles, and was always short. I then had a project that I had to calculate my ruffle lengths to my last inch of fabric. Since then I've gotten pretty good at calculating how much fabric I need to make ruffles.

A few assumptions first. I ignore a gore in skirt unless it is a very wide gore or a circle skirt.  For a wide gore, you'll need to break out the trigonometry if you want to be more exact, or assume the skirt is a circle. Circles you can use the diameter at the point of your ruffle. Also, ruffles are cut on the width of the fabric. Everything is calculated in inches, until you get your final measurement.

You need the following measurements:

Skirt Hem Width
Number of Ruffle Rows
Ruffle Density*
Width of fabric
Depth of Ruffle (including edge finishes)^

*Ruffle density is how thick you want your ruffle to be. Normally it is a ratio between 1.5 to 3. To figure out what you want play around with a 1 ft strip of fabric, get it to look how you want and measure your results. To get your Ruffle Density you divide 12 inches by the length of your sample.

^For your Depth of Ruffle, take your top and bottom seam finishes into account. I use a 1/2 allowance for the top of my ruffle. A pinked edge would have zero finish allowance, a small hem a 1/2 or less. Remember that in tiered ruffles need a small amount of overlap. I normally use 1/2 inch.

And here's your equations to get your yardage.

Skirt Hem Width x Number of Ruffle Rows x Ruffle Density = Inches of Unruffled Fabric

(and if your like me, it's an insane number. My last project came out to 25 yards! You don't convert to yards for the remaining math, but it's cool to know. This is also how much trim you need, if you're going that route.)

Inches of Unruffled Fabric / Width of Fabric = Number of Strips

The number of strips for how many widths of fabric you'll be cutting.

Number of Strips x Depth of Ruffle = Inches of Uncut Fabric

Lastly, you convert to yards.

Inches of Uncut Fabric / 36 inches per yard = Yards of Uncut Fabric

And you have your exact yardage you'll need for your ruffles and how many strips you need to cut. And then the fun begins.

Happy Ruffling!

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