# DIY Tips: Circle Skirt Formulas – Half, Third and Quarter

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I have been receiving a few requests to help people out with the maths behind my half circle skirt – Sorry guys, my maths explanation skills apparently suck :/

I will give you the equationss and the basics of both the circle skirt and the half circle skirt. This will help you guys understand the logic behind it.

The equation we will use is the formula for the Circumference of a circle – so the outer ring measurement.

The circumference is your waist measurement

In the next few diagrams, imagine the red centre circle represents your the length around your waist and the distance from the central circle to the outer circle is the length of your skirt.

# Full Circle Skirt & Half Circle Skirt

## Full Circle Equation:

Circumference (waist) = 2 x π x Radius

Radius = Waist / 2 x π

## Example:

My waist is 26 inches

Radius   =   26 / 2 x π    =   4.13 inches

## Half Circle Equation:

Circumference (waist) x 2 = 2 x π x Radius

Radius = 2 x Waist / 2 x π

## Example:

My waist is 26 inches

Radius   =   26 / π    =   8.2 inches

# Third Circle Skirt & Quarter Circle Skirt

## Third Circle Equation:

Circumference (waist) x 2 = 2 x π x Radius

Radius = 3 x Waist / 2 x π

Radius = 3 x Waist / 2 x π

## Example:

My waist is 26 inches

Radius   =   3 x 26 / 2 x π    =   12.4 inches

## Quarter Circle Equation:

Circumference (waist) x 2 = 2 x π x Radius

Radius = 4 x Waist / 4 x π

Radius = 2 x Waist / π

## Example:

My waist is 26 inches

Radius   =   2 x 26 / π    =   16.56 inches

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In every example given above, the greyed  out part is the unwanted part of the circle and is shown only to demonstrate the segments of the circle.

In terms of buying the right amount of fabric, make sure the meausrements according to the white areas of the diagram match how much fabric you’re going to buy.

Also, in case people were wondering what pi is:

I really hope this posts helps!

LOve <3

Yin

xx

## One Reply to “DIY Tips: Circle Skirt Formulas – Half, Third and Quarter”

1. This is like the holy grail for me right now. You can’t even imagine how excited I am. Your layout of the equations for circle skirts is one of the most clear I’ve come across in googling circle skirts. I’ve been wanting to do a third circle skirt for a while after seeing a pic on Burdastyle but couldn’t find a good explanation of how to do the calculation. I’m so excited to start breaking into my stash for the spring. Thank you so very, very much.