2. MATH STUFF! HUZZAH! i'll bet you love math as much as i do, so this part will be So Much Fun.

that middle hole is our circumference. that is the hole your feet go through (in case you were wondering). in order to cut an accurately sized hole, we need the radius of the circle. the radius is the distance from the center point of the circle to the outside edge.

for our example, we want the circumference to be equal to our hip measurement, which we will say is 40".

NOW...
let's pause for a minute. I'm not going to go into great detail about this, but there's something called 'bias' with fabric. It has to do with how the weave of the fabric effects the way the fabric lays.
Cutting on the bias will make the fabric stretch. When you make a circle skirt, you're going to wind up cutting part of it on the bias, no matter what you do, it can't be avoided. Even with a non-stretch, woven fabric, it will stretch. Stretch fabrics will REALLY stretch when cut on the bias.
So if you've ever made a circle skirt, and you've done ALL the math right, and it still turned out a little too big, we shall blame bias.
To counteract bias, we need to make the hole smaller than we think we need it. So we will subtract 4 inches from the 40" we are shooting for. That gives us 36".
I know 4 inches sounds like a lot, but trust me here. You always want to shoot for smaller with a circle skirt (unlike most other things where larger is more easily fixed), because that can be fixed by cutting the hole bigger!

to get the radius, we use this equation:

3. okay, take a deep breath... we're almost done. fold your fabric in half. and then in half again, so it's folded in quarters.
from the folded corner, measure
5 3/4" out from that point in several places, so that you have a quarter circle.
each point along the quarter circle should be 5 3/4" away from the center point.

if you want the skirt to be 8" long, add 8 (plus a hem/seam allowance, so we'll go with 10") to the 5 3/4" and draw a quarter circle around the smaller one, each point being 15 3/4" from the center point. go ahead and cut that baby.

that's it! now you should have one big donut. laying flat, the inner circle will measure 36", but when you open it up and stretch it out a bit, it should be closer to the 40" measurement that we want.

measure it just to make sure, and if you need to make it a little bigger, go ahead. just take a sliver off that inner circle to make it a little bigger. go slow, because like I said before, too big is harder to fix than too small.

attach it to your dress, skirt, or waistband, and you're done.

NOTE: depending on the size of your donut and the length you want your skirt to be, you might need to cut your donut into sections.
you might need to make it in 2 sections (so you'll have 2 half donuts, which you can then sew together) or 4 sections.
if you want to see it in action, look at the examples. the 2nd skirt (the stripey Misfits one) is cut into 4 sections. you can see the 2 front panels in the photo.

keep reading for variations on the circle skirt...

VARIATION 1

for extra "ruffly" circle skirts, cut two smaller donuts instead of one big one. the circumference of the hole in each donut should be half of the circumference you actually want.

EXAMPLE: your hip measurement is 40", but as mentioned above, we want to go a little smaller to be safe, so each donut hole should have a circumference of 18".

cut through each circle, and sew them together before attaching to your hem.

VARIATION 2

for pixie skirts, leave the outside edges of the donut square. the hem of the skirt will now be assymetrical.

this is a good one if you're in a hurry, because it's one less step.

you can sew several squares around the hem for a layered look.

VARIATION 3

this is a combination of variations 1 and 2.

cut two smaller squares, each having a circumference half of what you want the total to be.