So I wanted to make these little rosettes I kept seeing and it occurred to me that I already had all of the materials, but I did not see any clear instructions for the sizes of paper needed.  Then I realized that they are just strips of paper in circles, so I used the circumference formula: 

c=2*pi*r

Where c= the length of your paper, r=the height of your paper, and pi can be rounded to 3.14 and the size of the finished circle across will be 2 times the value of r.  Sounds a little complex, but I'll give an example.

Say I want a rosette that is 7" across. Then my strips of paper need to be 3.5" width wise and at least 22" lengthwise, but you should do at least 24" lengthwise since the paper is folded.  To go the other way, say I have paper that is 18" lengthwise, the biggest rosette I can get from that is going to be about 5.75" across, so to be safe, I should cut the width of my strip to about 2.5"-2.75" just to be safe so I'm not stretching the paper.  This formula will work for any size rosette and you can adjust your accordion folds based on appearance, but remember, the further apart your folds are, the more you "shorten" your initial length, so always try to have extra length so you don't tear your paper, happy crafting! 

Materials needed: 

Paper of your choice, I used K & Company Double Sided paper

Glue, I used Elmer's Craft Bond

Scoring Board, I used Martha Stewart

Button

Embroidery Floss and Needle

Scalloped Die Cuts, I used my Cuttlebug, but you can also use a punch

The above rosette is 3" across. I cut my paper 1.5" wide and 12" long. So I needed at least 9.4" length, but I wanted it to look "full" so I used the entire 12" length with 1/4" folds.

This was done using 20" of length and 3.5" of height, I did all of the folding and glueing and then cut 1" off the top to make 2 rosettes, 1 at 2.5" height (5" across when flattened) and 1 at 1" height (2" across when flattened) and then glued them together.