Measure the waist

Use this number to calculate the width of each skirt panel (front and back)

Add seam allowance (for the 2 side seams; typically 1" for each panel).

Measure the desire length of the skirt

Measure the width of the elastic.

Add seam allowance for the elastic waist, elastic width x 2 plus 1/4".

Add seam allowance for the hem (typically 1")

Cut 2 rectangles using these measurements.

As an example: Ellie's waist is 23", the measurement from waist to above knee is 17" and the elastic width is 1". We cut 2 rectangles of 24" by 20 1/4" as illustrated in the diagram below.

Measure the waist and then subtract 2"- 3", depending on what feels comfortable. If you're planning on overlapping the ends of the elastic you need to take that allowance into consideration too. This method is the simplest but will create bulk at the joining seam. To avoid that, use this tip for joining elastic ends or simply join them with a zig zag stitch, sewn 2-3 times. The tip mentioned is also great to use when you're running short on elastic as it will extend the elastic a bit.

Prepare the fabrics

Measure your waist.

Use these measurements to calculate the width of each skirt panel, adding 1" allowance to the width of each panel.

Measure from waist down to where you want the hem and add 3 1/4" (1" for the hem and 2 1/4" for the elastic waist)

Place the fabrics right sides together and draw a rectangle with the fabric marker, using the above measurements.

Pin the fabrics together and cut out the rectangle with your scissors.

Cut a piece of elastic that is about 2" smaller than your waist measurements.

Take the pinned panels to the sewing machine and sew the sides only with a 1/2" allowance.

Take the skirt to the serger and finish the side seams. Alternatively, use a zig zag stitch to finish the raw seams if you don't have a serger. Other methods for finishing the raw seams are highlighted in this tutorial.

With the seam gauge or the measuring tape and the fabric marker, mark 1/2" along the hem line, on the right side of the fabric.

Turn the fabric wrong side out.

Fold the hem up at the 1/2" marks and press well with the iron on steam.

Fold again and press.

Take the skirt to the sewing machine and sew the hem about 1/8" away from the inside fold.

Join the elastic ends with a zig zag stitch or using this method.

Divide the elastic in 4 and add a pin at these marks.

Repeat for the top of the skirt.

With the skirt right side out, attach the elastic to the top of the skirt at the 4 marks in both the elastic and the skirt. Then add 4 more pins in between these marks.

Sew the elastic to the skirt with a wide zig zag stitch, about 1/4" away from the raw edge.

Fold the elastic down.

Fold the elastic inside the skirt.

Then fold again inside the skirt.

Pin and sew with a zig zag stitch, close to the inside fold.

For this method you don't need to join the elastic ends before so leave the elastic as is.

To insert the elastic you'll need to create a casing in the top f the skirt.

For this, fold the top of the skirt inside 1" and press with the iron on steam.

Fold inside again 1" and press.

Sew around the casing, about 1/8" away from the inside fold. Leave a small opening, about 2".

With the help of a safety pin, insert the elastic through the casing until the ends meet.

Join the elastic ends as indicated above.

Top stitch the gap in the casing and even out the gathers.