Updated: Oct 8, 2020
Circle Skirt Project – Part 1
‘You live but once; you might as well be amusing!’
What’s more fun than a Circle Skirt?
When I was a little girl I had an orange dress and would get everyone to watch me twirl in it because I loved how it spun out around me and everyone remembers that iconic white dress worn by Marilyn. Short or long it’s that twirling feeling you get with a Circle Skirt, elegance and fun combined!
Intro to Circle Skirt
Circle Skirts can be the simplest of all garments to make and you can make one in little over an hour. Obviously depending on finishing’s and design options they can also be very complex, but in that respect, they meet the needs of all sewists regardless of experience. This is why I choose Circle Skirts for this Project.
This project is split into two Parts. This first Part holds technical detail about how Circle Skirts are created the second Part is a very simple stitch along to create a knee length half Circle Skirt with a waist band, the second part is not technical but intended for the user to just simply follow along and create a skirt in a very short period of time (and no prerequisites of learning from the Threadelicious ThreadBox are needed). Both parts will be placed in the Project area and available to all Threadelicious ThreadBox members. The second Part will also be added to the public blog to allow all members of the public to have a go at sewing along, this gives them an introduction to Threadelicious in a hope to increase our members to get a little more sharing and community spirit started.
As a ThreadBox member you are welcome to start this Project either by reading Part 1 to understand the concept of Circle Skirts more and consideration of some design options or just dive straight into Part 2 and make a skirt which is a great weekend Project to try and help you step out of the workflow to actually create something quickly for your wardrobe. Before you know it you may get a Circle Skirt addiction!
The Circle Skirt Concept
A Circle Skirt is made from a circle of fabric with the centre piece cut out also in the shape of a circle to enable the body to fit into it at a point around the waist, so then a circle within a circle if you laid it out flat. Given enough fabric you could cut out the skirt this way and have no Seam Allowances.
Image stepping into the Inner circle and pulling the fabric up to your waist. The rest of the fabric will drape down your body creating a fullness and volume in the skirt without the need for gathering or pleating at the waist just a very smooth fit.
Therefore, a Full Circle Skirt is a very full skirt.
With that simple notion in place let’s look at a half Circle Skirt.
This on paper looks like the full Circle Skirt cut in half.
Imagine joining the two cut lengths or sides together, you would end up with a cone shape with the centre cut out. Now image stepping into that cone and pulling it up to the waist. The circle (when the seams are joined) fits around the waist. The rest of the skirt drapes down the body and the volume effect is less than that of the full Circle Skirt, half the volume. Less fabric is used to create the half Circle Skirt.
Let’s look at further divisions of the circle, firstly the ¾ Circle skirt.
Using a similar concept to the half Circle Skirt this skirt when the seam is joined has less fullness than the full circle but more fullness than the half Circle Skirt, obviously!
Finally the quarter Circle Skirt.
Which has minimal fullness to the drape, and on larger hips to waist ratio can be a harder skirt to pull off (quite literally!).
On the face of it these skirts are very simple to make as they can be made with only one seam and no waistband, of course you can add extra seams in around the body and you can add a waistband, closures and then there is a hem. You can also add extra features such as pleating or pockets or add a bodice to make into a dress. This is where your workflow learning in the Threadelicious ThreadBox will start to open up some of these extra design features.
There are also many other types of Circle Skirts, for example double circles, third circles and so on which are not covered here but will give you some food for thought if you get interested in Circle Skirts.
In order to create a Circle Skirt you only need 2 measurements, the Waist Circumference and the Skirt Length, which can be any length you like even Bridal trailing onto the floor. The only thing that limits your length is the width of your fabric, and if the fabric is not wide enough you can always split the skirt into different panels which will create seam lines. Circle Skirts can use quite a lot of fabric in fact so be willing to get your purse out if you want a long one.
As fabric width is so important with this kind of skirt you need to be sure how much fabric you need and how wide it needs to be, before you go shopping, which we will cover later but in order to work out this plan of action a little bit of maths is in order so next put your thinking cap on.
Hopefully you are with me so far, I am going to make this as simple as possible so don’t be frightened away with the maths because remember the maths that you learned at school that you never thought you would use again well…..here we are you can take it or leave it.
The goal is to read this unit and understand the concepts being discussed.
Circle Skirt Calculations
Before we fit your measurements into the calculation let’s have a look at the formulae.
Now I might add that if you google Circle Skirts you will come up with a variety of ways to make them with varied formulae options.
What you see here is my tried and tested version of solving the equations for each skirt and I write them here for you as a solid starting point for you to work with however I will caveat that I have not made skirts larger than a size 18 but as long as you create test garments first to check everything fits then you should be good to go into any size with these calculations.
Firstly let’s start with some simple maths.
is read ‘Pie’ and its value is 3.142, we will just be using Pie to three decimal places.
The formulae for the circumference (C) of a circle is;
In other words, the Circumference equals two times Pie times Radius
We will look at how this works for each of the different Circle Skirts defined above.
We already know what the value of Pie is, and we already have the value for the Circumference as this figure relates to the Waist Circumference measurement. What we are aiming to find is the radius value of the circle.
The following shows how each formulae is transposed, but it is also important to understand how design choices will change the formulae so that you can be flexible with your designs whilst still getting accurate calculations, we will be coving some of the more important design choices so that it is clear how these affect the formula.
Full Circle Skirt Formulae
We learned above that the circumference of a circle is;
If we transpose the Waist Measurement (WM) into the formulae we can say
Which when worked through to find the radius because we know what the WM is or we will do when we actually measure it.
This equation would then need to be solved to give the Radius.
Before we look at how to solve the equation lets quickly get the formulae for all of the different types of Circle Skirts defined above.
Half Circle Skirt Formulae
If the Circumference of a circle is
The Circumference of half a circle is
Quarter Circle Skirt Formulae
For the Quarter Circle Skirt
In other words
Three Quarters Circle Skirt Formulae
For the Three-Quarter Circle Skirt.
The final formulae in red is correct for the Three-Quarter Skirt.
I wanted to transpose this backwards for you but can not find anywhere online or otherwise to check my originating formulae. Here are my thoughts anyway, anyone please feel free to add their comments on this one I am open to suggestions.
In other words
To consolidate here are all of the formulae in a table for quick reference in order of skirt volume.
Circle Skirt Formulae Table
Solving the Formulae with an Example
In order to find the Radius we need to put in a Waist Measurement.
We are using the Waist Measurement of the half-sized body form in order to demonstrate the calculations. Eventually you will be putting in your own measurements for Waist Circumference.
The Mini Body Form Waist Circumference Measurement 12 5/8” (if you prefer you can work in cm when you do your own calculations in Part 2).
Using my method of creating a Circle Skirt it is important to consider how tight you measure the Waist Circumference. I find that if you measure tight you will get a tight result, measure slack and your skirt will be slacker at the waist.
For this example the Mini Body Form was measured tightly.
If you review the table below you can see how each formula for each Skirt Type is worked through and resolved.
Notice how as the volume in the Circle Skirt decreases the radius increases. A longer radius pushes the Waist arc line out to create the space for the waist and because we fold the fabric differently for cutting the different skirt types we resolve this. We reveal this as we look at each of the samples being made for the Mini Body Form below.
Mini Dress Form Mockups
It is important at this stage to know that we have not finished with the formulae yet there is more that we have to do.
In order to explain what needs to happen to the formulae I wanted to show you what would happen if we simply use the formulae we have resolved up to this point by creating mock up skirts for the dress form.
We will set the Skirt Length to 10 inches.
Full Circle Skirt
Remember from above we worked out the following;
Radius = 2 Skirt length = 10
To create the full Circle Skirt we are going to cut the circle from one piece of fabric similar to the circular diagram we looked at before. As our fabric is large in proportion to the model size we can do this on one piece of fabric for the mini body form. The fabric is larger than 2 times the skirt length + radius in both width and length.
The fabric is folded down (fold at the top).
Then the fabric is folded again like a book but with the original fold at the top, so there are 4 layers of fabric.
From the point where all the folds come together measure down 2” pivot the measuring tape and measuring 2” again, pivot again until a 2” arc has been marked out for the Radius.
These marks are joined with an arc line either by hand or with a curved tool. This line is the Waist Circumference.
To find the base of the skirt add together the Radius and the Skirt length for a Total Measurement, 2+10 = 12.
Measuring again from the point where the folds come together but this time measuring and marking 12”, pivoting the measuring tape measure 12”again and mark, pivot again and mark and repeating until an arc is marked out for a 12” Radius to give the Base line for the skirt.
Again using freehand or a curved tool to join up the marks for the arc.
Incidentally if you did not draw an arc for the base of the skirt and simple measured down the sides for the total length (top and side) and drew straight lines to create a square rather than an arc line you would end up with a handkerchief hem.
Cutting through all layers of the fabric the Waist arc line is cut and the base arc line is cut.
Here the skirt is opened out
In order to get the skirt on the body form (as there is no stretch in this fabric) we have cut between the two arcs in a straight line to open out the skirt.
Now lets look at something rather interesting…..
If we straighten out the Waist line on the skirt and measure it you can see that it does not measure the same as the Waist Measurement that we initially wanted, it is bigger.
So what causes this?
There is a combination of a few factors affecting this measurement;
Imperfect calculations (such as not using full pie in the calculations or rounding up or rounding down during calculations),
Imperfect marking and freehand curves,
But one of the biggest factors that effect this is the Bias stretch of the fabric. This is a woven fabric and as we straighten the Waist curve we are opening up fibres and therefore the circle stretches out. It is important to note that different fibres woven in different ways will have different bias stretch.
So what does this mean?
It means that if you simply use the formulae as is the skirt will be too big (note we have not discussed seam allowances at this point).
How do we know how much too big the skirt is? This is a tricky one! The answer is after all that maths, this really is not an exact science after all!
But don’t dismay we are going to use this to our advantage!
The solution is a very simple one and seems to work like magic!
The trick is to take off 2” from the original waist measurement (no matter how big or how small the waist) before you even start resolving the calculations.
If you google this you will come up will a variety of takes on what works and what doesn’t but no one seems to mention much about this magic 2 inches.
After my own testing this is the adjustment that I make. Feel free to test your own theories! My caveat is that I have not tested every single waist measurement with this theory so beware there is an element of risk with this but that is why we always make test garments to get as close as possible isn’t it!
I am actually at a loss as to what to call this 2” adjustment so for now I will just call it 2” Bias Stretch Adjustment.
So taking this Bias Stretch Adjustment in to consideration the Calculations table for the mini body form will change to look like this…
Bias Stretch Adjustment Table
Using this new table of adjusted Waist Measurement we can start again with creating the samples for the Mini Dress Form. Please note that up to this point we still have not discussed seam allowances!
Full Circle Skirt
Created as above but using the adjusted Waist Measurement of 1 6/8”.
And voila here it is on the dress form – a perfect fit!
Here it is in Back.
Notice how the back seam fits perfectly (I cut the circle to get it on the body form for now). There are no seam allowances this exercise is simply a method to show how the formulae creates the fit and to show the different flares of the skirts.
This fabric is a quilting cotton so has a slightly stiff hand, image this in a cotton lawn or any other softer fabric, you can see how it will fall more softly down the body. But even in this fabric you can see how voluminous a full Circle Skirt is, very 1950’s, a little petticoat of tulle would not look amiss under all this volume.
Three Quarter Circle Skirt
This skirt is cut similarly to the Full Circle Skirt in that the fabric is folded twice, then at the end a quarter of it is cut away so there is a certain amount of waste.
Ensuring as before that the piece of fabric is twice as wide and long as the radius + length the fabric is folded in half then half again like a book and the radius and length are marked and drawn as before, the only difference is that the radius is a different figure this time.
Before opening out the skirt, because a quarter of it needs to be cut away I made some little marks at the centre and the edge of the quarter piece.
Once opened up those lines can be joined up
And the quarter is cut away.
Here it is draped on the dress form.
Half Circle Skirt
Ensure that the fabric is twice as wide as radius + length and at least as long as radius + length. I have only folded the fabric once.
With the fold at the top ensuring the left side is cut straight and squared off to the fold.
3 3/8” radius was measured out for the first arc for the Waist.
Then 13 3/8” was measured from the point pivoting and marking all the way around to allow for the 10” length.
The Arcs were then cut out
And here it is opened up revealing the half circle.
And here is how it drapes on the dress form.
I have to say out of all of them the Half Circle Skirt is my absolute favourite!
Quarter Circle Skirt
The Quarter Circle Skirt is the least flared of all the skirts.
This is made from one square of fabric that is at least as wide and long as the radius + length.
This square of fabric is then folded selvage to selvage opposing sides to create a triangle on a 45 degree bias, simply for ease of marking and cutting.
The radius is marked at 6 6/8” and the 16 6/8” arc is marked to ensure a skirt length of 10”.
The arcs are cut
When opened out you can see how the shape is a quarter of a circle
Here it is on the dress form.
Not only is this skirt using less fabric and therefore less flare, it also has less stretch across the waist and hips, so if you have large hips beware of the quarter Circle Skirt, you will need to factor in some wearing ease on this skirt if you have any hips at all!
With at least (because there are more options) these four different variations on a Circle Skirt and each can be made in any length you have infinite combinations of skirt to pick from. Imagine each as a Mini, as a Midi or Ankle length.
Each skirt can be made with any number of other variations such as made with a Facing and or Lining to finish off the top. Or made with a Waistband. The base finished off with a hem. Pockets anyone?
Then there is the fabric choice, a woven fabric would need a closure such as a zip, a stretch knit could have an elasticated waist. If you are using a sheer fabric, you can cut a lining in the same way and for a quick result pin them together and stitch as is they are one piece of fabric to attach a waistband etc. (of course there are more couture ways of attaching a lining, it depends on the finish that you are after). If you really like the Circle Skirt you could create an underneath skirt/petticoat that you could wear under all of your skirts, reducing the making time for each skirt.
Imagine your favourite combination of skirt in a print.
Then we can also start to cut the skirt up into any number of panels. For example a woven fabric may have three panels, one for the Front with the Back cut into two halves to allow a zip to be inserted.
Of course each skirt could be added and trued up to a bodice and so be made into a dress.
But there is the little thing of Seam Allowances that we still have not look at yet.
So we have a little way to go yet in order to complete any design for the Circle Skirt.
Circle Skirt Creation
We have so far looked at a Mini Body Form mock up. But we need to look a little more at the Circle Skirt in order to understand how to actually create it.
There really are two main ways to create the Circle Skirt (or one of its iterations) to draw straight onto the fabric as above or the other option is to create a pattern for the skirt.
Now I know this seems obvious but it is worthy of a statement because depending on which option you choose you deal with things like seam allowance, panelling, hems and other design features slightly differently.
If you are going directly to mark and cut the fabric without a pattern you will need to factor in things like seam allowances into your basic formulae to ensure the resulting fabric is cut correctly.
If you are creating a pattern as with all drafted patterns Seam Allowances can be added after the truing stage so this is a better option if you wish to cut the skirt up into multiple panels or add a zip or add a bodice or use different seam allowances for different skirts or add pleating or tucks or add pockets etc. The basic Circle Skirt pattern (and its iterations Full, Three Quarter, Half and Quarter) can sit alongside your other Skirt Working Templates created from the Threadelicious ThreadBox and in fact becoming Circle Skirt Working Templates.
So we really need to cover both aspects.
Marking directly to Fabric
Let’s look at cutting directly on the fabric first, just like we did above.
The first thing to say here is pretty obvious, measure and measure and calculate and calculate again before you cut because once you have cut if you are wrong you will end up playing a different game called ‘make it work!’.
This is where we come back to that 2” Magic Bias Stretch Adjustment.
2” just happens to give us a very comfortable amount of seam allowance for 2 seams, either placing the two seams in the sides of the skirt or one in Front and one in Back. That gives 1” per seam, i.e. ½” for each piece of fabric in the seam!
The logic is simple, if you are going to have a Seam Allowance/Allowances in the skirt you need to work out what size Seam Allowance you are going to use and then multiply that by two (to include both sides of the seam) for each seam you need. This resulting Seam Allowance figure gets added back onto the initial Waist Circumference Measurement (after you have taken off the 2” bias stretch adjustment).
As an example for the Full Circle Skirt (adjusted to remove the Bias Stretch Adjustment) above where we had a formulae of;
If we wanted one seam in the back of the skirt with ½” seam allowance we would be adding 1” to the Waist Measurement after taking off the 2” for the bias stretch adjustment.
So the formulae would read,
And let’s resolve that equation
So we end up with a slightly bigger radius than the initial 1 6/8” radius without the seam allowance which is what we would expect (because we added 1” back on).
Even if you didn’t want seams in your skirt sometimes you have no choice if the fabric is not big enough to fit your skirt onto and you will only know this when you have determined the radius and length.
We have one really interesting point to make here, if you are happy with 2 seams in your skirt you don’t need to take off the 2” Bias Stretch Adjustment because you can use that fabric for your seam allowances!
When creating the sample skirts for the mini Body Form they were made very accurately and the Waist Measurement was taken tightly on the waist.
But in real life waists are different every day and you may want a little wearing ease in the skirt especially for the Quarter Circle Skirt or if you are making the skirt from a knit fabric and you want a little extra ease to allow a stretch to get the skirt over wider hips. You would treat wearing ease the same as you would a seam allowance in that you would define how much you feel you need across the whole waist circumference and then add this amount to the Waist Measurement, after you have taken off the bias stretch adjustment and added on your seam allowances. You could be adding anything up to 2” for wearing ease but typically 1/2” may well be sufficient.
For example a Circle Skirt with 1” of seam allowance (for 1 seam) and 1” of ease after taking off the Bias Stretch Allowance of 2” i.e. one negates the other the radius would be,
When cutting directly on the fabric you will also need to consider the skirt length a little more because you will need to determine the length of the skirt you require, the hem size and any seam allowance needed at the top of the skirt to use for a waistband attachment.
If a waistband is going to be used you will also need to consider where the waistband is going to sit, above the waist? – then only the Seam Allowance would be required, below it? - then the skirt length would need to be reduced by the waistband height potentially. Once you have determined all of that you are going to be closer to working out how much fabric you are going to need.
There are so many variations to working out the Skirt Length so let’s look at just one example.
Let’s consider planning a Circle Skirt with a 2 inch waistband sitting on the waist (so the band extends up past the waist – as the body increases in size as you go up past the waist you may need to consider adding in a little wearing ease to the skirt as noted above). The Skirt would have one seam in the back to install a zip.
If we were to use a 1/2” seam allowance to attach the skirt to the waistband we would need to subtract 1/2” from the radius (after doing everything else i.e. adjustments and allowances). This reduces the radius, actually allowing for two radius arcs to be drawn one for the Waist i.e. the sewing line and one for the seam allowance to attach the waistband. It can help to mark the fabric with the sewing line and the cutting line to ensure that you know you are cutting the correct arc out!
So a Circle Skirt with 1 seam allowance for a zip in back with a ½” Seam Allowance to secure the Waistband, the formulae for the Radius would be,
The Waist Line Arc to draw would be,
We would then take off ½” for the waistband
The Hem will affect the Skirt length measurement not the Waist Radius. Also dropping the Waistband or a dropped waist into the Skirt length would be the other design feature that would affect the skirt length.
As Circle Skirts are difficult to hem as the fabric is all cut on a strong curve with lots of bias thrown in for good measure, a slim hem is a good choice. As you turn the hem you are bringing up a wider circle to fit inside a smaller circle so a little easing or small tucks may be required to control the excess. With fine fabrics and a wider hem you are really looking at a hand sewn hem to control everything and give the best result. So with a Circle Skirt especially in a knit don’t overlook a surged hem or a raw edge.
The hem allowance is added to the skirt length figure.
In our case with the Mini Body Form the Skirt length is 10” we could add a ½” Hem allowance and then the Skirt Length would be 10 ½”.
As before this figure is added to the radius figure to give the total length that is used when drawing out the total length arc which is then cut for the bottom of the skirt.
Considerations for Pattern Drafting
If we had done the calculations and measured the arcs on to paper rather than fabric we can then use this as a pattern that would require design features, pattern notes and testing. As you go through the Threadelicious ThreadBox this will become clearer to you.
When we look at the initial shapes of the skirts when laid out flat we know that the Waist arc will fit on the waist no matter which skirt we are making. Therefore the shape can be cut into as many panels as required you would simple measure or fold and cut.
For example if you wanted the Circle Skirt cut into for panels for two in Front and two in Back of the skirt you would simple fold the shape into half and cut on the fold then fold each half again and cut on the fold resulting in four separate panels.
Once you have this basic Circle Skirt Working Template you can then add in other features that were covered in Module 6 - Create the Flexible Pattern - 5. Drafting Skirts and also Auxiliary Reference Information - Draft - Pleating.
You would do this initially without consideration for seam allowances in the formulae so you would need to remove the Bias Stretch Allowance in your calculations. You would then after drafting a pattern from your Circle Skirt Working template add seam allowances where required to join each panel or to attach a waistband, add your hem, mark pockets or other design features.
Working out Fabric Required
Let’s leave the world of the Mini Body Form for a while as we contemplate fabric requirement because unless you have a small enough waist or the skirt length short enough or the fabric wide enough then you are going to have trouble fitting the skirt on the fabric. Fabric is usually supplied at 60 inch or 44 inches wide of course there are variations to this.
Consider if you wanted to make a 30” waist circumference Circle Skirt with no seams in a maxi length of 40 inches with no waistband you were going to face the skirt on the inside with a 3 inch facing and a rolled or overlocked hem.
The radius would be,
The length is 30” (the amount taken up by the overlocked hem is negligible).
The Total length to draw out the base of the skirt is therefore 34 1/2” which multiplied by 2 (because you have to fold the fabric for a Circle Skirt so the length has to be doubled) this gives 69” which as we know is far too large to fit on a 60” wide piece of fabric, the length is ok but we have to fold two times so we would not make the measurement in the width. Infact for most measurements you are going to struggle to make a Circle Skirt on one piece of fabric unless you are small and are making a minis skirt.
To get around this issue you will need to cut two pieces of fabric to create the Circle Skirt so you will have 2 panels or joins. Instead of folding the fabric twice (down then across) you would have to fold the fabric once (down) the length of which would be 69” you would mark and cut this piece then do this again for a second piece.
For any of the Circle Skirt variations you are going to have to, determine your design features and calculate the radius and length then add the radius and length together to decide if it will fit on your fabric. If not then you will need to break down the skirt into different panels which consequently adds on extra seam allowances which you will have to factor back in again. It feels clunky but if you are understanding what you are doing and why you can simply work methodically along.
There are various Circle Skirt calculators on the internet but unless you understand and know how they get to their figures and if they have enough permutations within that to cover all of your design decisions you are never going to know if they are accurate for your needs. In the end although it takes a little longer, if it is more control and accuracy that you are looking for then do your own calculations. The online calculators are good to give you a guide but you may end up playing that ‘make it work game’ again.
I hope reading this Part has helped you understand the main points to consider when working on a Circle Skirt. The information in this Part is intended to give you a really good grounding with the science behind circle skirts and although detailed it is a resource you can revisit as you get more creative with your Circle Skirts!
After all of that thinking move on to Part 2 which for now takes quite a lot of the thinking away from you and you can make a Circle Skirt up really quickly for anyone in the family.
After you have had a little practice have a go at your own Circle Skirt design!
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