Tutorial 14. Calculating Adjustments to the Standard Pattern.
It is time to carry out all necessary calculations and adjust the standard pattern after my client’s individual measurements, i.e. her particular body size.
You can see all required measurements in the table below:
Judging from your e-mails and forum questions, I can tell that some of you still don't feel confident about these calculations. Thus let me talk about the values written in the table and explain the basics one more time.
This information will be particularly useful to those who have got acquainted with the Corset Academy recently.
You can draw a table for calculating adjustments to the standard pattern in a plain notebook or use computer software like Excel or Word.
The table contains a list of measurements required to figure out adjustments to the standard pattern (the base of the dress) enclosed with this course.
- Bust Width Front,
- Under-Bust Width Front,
- Bust Circumference,
- Under-Bust Circumference,
- Waist Circumference,
- Stomach Circumference. Make sure to record the distance from the waist in brackets. I took this measurement 12cm below the waist.
- Bust Apex to Bust Apex. Let me remind you that this measurement is actually taken between the supposed bust princess seams.
- Clip to the armscye; to the corner (the top of the cup); and to the neckline.
- Side Length. This measurement is taken from the waist. It is highly recommended that you measure the longest possible length which is not to be exceeded. I am talking about the longest possible side length at which the armscyes of the dress will just about start digging into the armpits.
- Under-Bust to Waist. I took this additional measurement because I know that my client has a short height and, therefore, a short torso. This will affect pattern adjustment calculations so I need this measurement to do them correctly.
The first column of the table contains client's measurements. There are free tutorials on our website where I demonstrate how to take these measurements. These tutorials are available on our YouTube channel and are part of many of our previously published teaching materials.
The second column of the table contains measurements taken off the standard pattern enclosed with the course. I highly recommend you should sew a mock-up after printing it out. It is enough to do it just once: you won't have to sew and measure a new mock-up each time.
Sewing a mock-up is absolutely compulsory if you are working with a pattern for the first time. Simply cut all pieces from mock-up fabric. Any plain cotton fabric can be used as mock-up fabric. The only requirement is having no stretch yarn.
After cutting the pieces, join them along the vertical lines, put the mock-up on the dress-form, and stuff all hollows to imitate your client's body. Now you can take measurements off your mock-up the same way you would take them off a person.
The thing is everyone has their own manners and habits when it comes to taking measurements, adding seam allowances, etc. Your values will not necessarily coincide with mine. It is your own standard pattern, your own dress-form, and your own mock-up and measurements. By sewing mock-ups, you will develop a proper understanding of how to work with patterns!
Please do not be lazy to do it. It will make further work a lot easier!
Before I start calculating adjustments to the standard pattern, let us compare pattern measurements and client's measurements. Even a quick glance at the values will tell you that the client's measurements are a lot smaller than the original pattern measurements. It is therefore obvious that I will need to adjust the pattern down.
Let us begin calculating.
You should always look at Bust Apex to Bust Apex before proceeding to the main calculations.
Bust Apex to Bust Apex: my client’s measurement is 18cm and the pattern measurement is 20cm.
18cm – 20cm = -2cm
This means that the central front part of the dress needs to be made 1cm smaller from either side. Simply shift the pattern 1cm outwards from the fold line of your fabric to achieve this.
I write it down in column 3.
But if you shift the pattern against the fold line, you will thereby make it smaller along the full length. To keep this in mind, I write -1cm in all lines of the column that refer to circumferences.
It is a very important adjustment so I always make a separate column for Bust Apex to Bust Apex.
After calculating adjustments to the Bust Apex to Bust Apex measurement, I need to define the configuration of the side seam line: first for the front and then for the back half of the garment.
All calculated values will be written in column 4 (Side Seam Front).
The configuration of the front side seam line is determined by two measurements: Bust Width Front and Under-Bust Width Front. Both are taken as distance between side seams across front.
Bust Width Front: it is 47cm on the client and 49cm on the pattern.
In order to arrive at my client's measurement, I need to shift the side seam line inwards at the bust line level so as to make the pattern smaller.
But I have already adjusted it down by 1cm from either end of the bust line, i.e. a total of 2cm.
49cm – 2cm = 47cm
This means I have already arrived at my client's measurement and there is no need in shifting the side seam line at the bust line level. I write a zero in line 1 of column 4.
Under-Bust Width Front: it is 38cm on the client and 40cm on the pattern.
In order to arrive at my client's measurement and make the pattern smaller, I need to shift its side seam line inwards at the under-bust line level.
But I have already removed 1cm from either end of the under-bust line, which makes a total of 2cm.
40cm – 2cm = 38cm
This means I have already arrived at my client's measurement and there is no need in shifting the side edge at the under-bust line level. I write a zero in line 2 of column 4.
Since there are no changes at the bust line and at the under-bust line, I will leave it as is for the whole front half of the pattern. The adjustment was accounted for in the Bust Apex to Bust Apex measurement when the whole front of the standard pattern was narrowed by 2cm.
Let us look at the Clip.
- Towards the armscye: it is 11cm on the client and 12.5cm on the pattern.
11cm – 12.5cm = -1.5cm
I need to shorten the clip by 1.5cm.
- Towards the corner: it is 11cm on the client and 12.5cm on the pattern.
11cm – 12.5cm = -1.5cm
Again, I need to shorten the clip by 1.5cm.
Towards the neckline: it is 6cm on the client and 7.5cm on the pattern.
6cm – 7.5cm = -1.5cm
I need to shorten the clip by 1.5cm.
I write -1.5cm in line 8 of column 4.
Now the clip will be proportionate. Adjustments to the clip toward the armscye always coincide with adjustments to the front side seam line. In this particular case, the side seam line of the front half of the standard pattern got shifted 1cm inwards after adjusting Bust Apex to Bust Apex. When I start drawing the customized pattern, the armscye line will naturally tend to be about 1.5cm shorter than before.
Things are now clear with the front side seam line.
I can move to the back side seam line then. Let's make some preliminary calculations and write all adjustment values into column 5 (Side Seam Back).
Let’s begin calculating. We will see what happens after I take into account all measurements and calculations from the table.
Bust Width Front and Under-Bust Width Front are not involved in these calculations. I write dashes in the table.
The only relevant measurements are Bust Circumference, Under-Bust Circumference, Waist Circumference, and Stomach Circumference.
I start from the bust circumference. It is 88cm on the client and 92cm on the pattern.
I have already narrowed the centre of the pattern by 1cm from either side, i.e. a total of 2cm.
92cm - 2cm = 90cm
88cm – 90cm = -2cm
There is, therefore, an excess of 2cm left on the pattern and it needs to be distributed between the two side edges of the back. In other words, I need to shift either side edge of the back 1cm inwards at the bust line level. I write -1cm in the table.
The next measurement is Under-Bust Circumference. It is 73m on the client and 82cm on the pattern.
I have, however, already removed a total of 2cm in the centre of the dress.
82cm - 2cm = 80cm
73cm– 80cm = -7cm
There is, therefore, an excess of 7cm on the pattern. It needs to be distributed between the left side edge and the right side edge of the back. In this case, I need to shift either side edge of the back 3.5cm inwards at the under-bust line level. I write -3.5cm in the table.
Let us look at the Waist Circumference now. It is 67cm on my client and 77cm on the pattern.
I have already narrowed down the centre of the pattern by 1cm from either side, i.e. a total of 2cm.
77cm- 2cm= 75cm
67cm – 75cm = -8cm
I need to narrow the back down by 4cm from either side at the waist level to bring the pattern to my client’s size and ensure a good fit in the waist. I write -4cm in the table.
Now let’s look at the Stomach Circumference taken 12cm below the waistline.
As you know, I am sewing for a long distance client. We were not decided on the final style of the dress when I took this measurement off her at the standard distance from the waist (12cm). Later in work, I decided to make the flare begin 10cm and not 12cm below the waist. This means I need to know my client's stomach circumference taken 10cm below the waist but, unfortunately, it is impossible to do this at the moment.
Instead, I will do all calculations with the Stomach Circumference taken 12cm below the waist and then shift it 2cm upwards on the adjusted pattern.
It is 86cm on the client and 97cm on the pattern.
But I have already narrowed down the centre of the pattern by 1cm from either side, i.e. a total of 2cm.
97cm- 2cm = 95cm
86cm – 95cm = -9cm
In order to bring the pattern to my client's size, I need to remove 4.5cm from either side of the back at the stomach line level. I write -4.5cm in the table.
I want to show you an example of how you should analyze the results.
I have worked on lots of "blind" orders from wedding fashion ateliers when all I knew was client's measurements. I never saw the clients themselves – not even in pictures. I could imagine the client's body shape with certainty just from looking at the given measurements and comparing them with my pattern which I knew like the back of my hand. It is enough for me to see the measurements to know the woman's body type. Judging from the relatively small adjustments to Bust Width Front and Under-Bust Width Front, I can tell that my client has a rather full bust in proportion to her body. At the same time, she must have rather narrow hips because there is little difference in measurements between the bust line and the under-bust line, which means she is not a big-boned woman. My client has a thin waist and narrow hips. The regular Hip Circumference measurement is not relevant because the flare will begin above the hip line.
In general, here is what my client's measurements tell me about her figure: she is small and slender with relatively large breasts and narrow hips.
Let us continue analyzing changes to the back side seam line.
If there are no changes in the side seam line of the front, then I need to adopt a single fixed adjustment value for the side seam line of the back to achieve the same configuration.
I need to preserve the original beautiful shape of the side seam line.
I suggest adopting a fixed adjustment value of -1cm and using front and back princess seams for all other changes. That is to say I will only arrive at the right circumferences by shifting the princess seams of the standard pattern.
I write -1cm in all lines of column 6 (Side Seam Back Adjusted).
In short, I leave the front side seam line unchanged and make the central front piece smaller by shifting it against the fold line of the fabric. The entire back side seam line is shifted 1cm inwards.
Further calculations imply working with princess seams. The lacking adjustments to the back side seam line are to be re-distributed between the front and the back princess seams.
-Since all calculations are done for a half of the dress, keep in mind that this half includes one back princess seam and one front princess seam, and each princess seam is two edges sewn together;
- You must never shift the front princess seams at the bust line and the under-bust line level;
- All calculated values are to be written down in columns 7 and 8.
I compare adjustment values of the side seam line and the adjusted side seam line of the back along all key circumference lines.
Bust Line. The side seam line needs to be shifted 1cm inwards. I have accounted for this so there is no need in shifting the princess seams here. I write a zero in the table.
Under-Bust Line. I need to shift the side seam line of the back inwards by a total of 3.5cm but I have only shifted it 1cm.
-3.5cm – (-1cm) = -2.5cm
I need to additionally adjust down the standard pattern by this 2.5cm. I transfer this value to the back princess seam.
This means either raw edge of the back princess seam needs to be shifted 1.2cm inwards at the under-bust line level:
-2.5cm / 2 = -1.2cm
I record the value into the table.
As you can see, there is a 1.2cm shift inwards in the area of the back princess seam that starts at the bust line and stops at the under-bust line. A shift like that is acceptable and technically possible.
But there will be more significant changes at the waist and the stomach level. Starting from the waist, I can additionally use the front princess seams for changes to the back princess seams. I will thus shift the back princess seam lines 1.2cm inwards along their full length and account for the lacking adjustments by shifting the front princess seams.
I write -1.2cm in column 7.
This will allow me to stick as close as possible to the initial shape of the princess seam. Although there are no changes to the back princess seams at the bust line level, they are shifted inwards by the same value (1.2cm) starting from the under-bust line level. The remaining adjustments (which are actually very small) will be applied with the help of the front princess seams. It is very easy. When I start drawing the adjusted pattern, you will see that the princess seam lines naturally turn out smooth and graceful.
I continue comparing adjustment values of the side seam line and the adjusted side seam line of the back along all key circumference lines.
Adjustments to the front princess seams are written in column 8.
Waistline. The side seam line of the back was shifted 1cm inwards and another 2.4cm was removed by shifting the princess seam lines. I need to remove a total of 4cm though.
-4cm – (-1cm) – (-2.4cm) = -0.6cm.
I need to adjust down the standard pattern by another 0.6cm. I write it under the front princess seam line.
This means either of the two edges sewn together by the front princess seam needs to be shifted 0.3cm inwards at the waist level:
-0.6cm / 2 = -0.3cm
I write the value in the table.
Stomach Line. The side seam line of the back was shifted 1cm inwards and another 2.4cm was removed by shifting the princess seam lines. But I need to remove a total of 4.5cm.
-4.5cm – (-1cm) – (-2.4cm) ≈ -1cm.
I need to adjust down the standard pattern by another 1cm. I write this adjustment value under the front princess seam.
This means the front princess seam lines need to be shifted 0.5cm inwards at the stomach level:
-1cm / 2 = -0.5cm
I write the value in the table.
It will be very easy to narrow the waist and the stomach by the resulting values using the front princess seams.
Now I need to decide on the Side Length. My client's measurement must not exceed 18cm as compared to 21cm on the pattern.
18cm – 21cm = -3cm
This means I need to shorten the initial side length by 3cm along the front and along the back.
Let me remind you that you can only shorten the side length by 1-1.5cm at the armscye. Two centimeters is as far as you can go!
But when the difference is 3cm, like in our case, you must never shorten the Side Length by removing the excess from the armscye end! Even if I did not know my client's Under-Bust to Waist, I would still be able to tell that her torso was shorter than the supposed torso of the standard pattern. If I trim the armscyes to make the Side Length 3cm shorter, then my client's bust line and the bust line of the standard pattern will be positioned at different levels.
In this case, the dress will have a poor fit in the chest.
You must always compare two measurements: Under-Bust to Waist (torso length) and Side Length. In other words, you must always compare the side length with the woman's height. If a person is short, then the distance between the under-bust line and the waistline will differ from that on the standard pattern. You will eventually learn to visualize it all in your head. If you place the bust line higher than your client's natural bust line, you can forget about a good fit in the bust!
There is an easy way out though. I will demonstrate it when drawing the adjusted pattern on paper. All four parts of the pattern need to be cut up along the waistline and then I will put their halves back together with a 1.5cm overlap thereby removing a total of 3cm from the side length.
The waistline will then draw nearer to the under-bust line and I will achieve the desired value of Waist to Under-Bust (10cm).
If you look at the bottom of the writing board, you will see all measurements taken off my petticoat sitting on the dress-form.
The following measurements will be used in further pattern construction:
- Skirt Length Back - 126cm;
- Skirt Length Along Back Princess Seam - 124cm;
- Skirt Length Side - 123cm;
- Skirt Length Front - 119cm;
- Skirt Length Along Front Princess Seam - 120cm.
Now that we have made it clear with the calculations, let us talk about the cutting.
I will adjust the standard pattern in accordance with client's measurements down to the level of the stomach line 12cm below the waist. I decided not to go further down to the hip line.
Then, I will calculate the flare of the skirt.
It is good to take two additional measurements to calculate the flare more precisely: Stomach Width Front and Stomach Width Back. But it is not a big deal if you haven't taken them! Simply divide your client's Stomach Circumference in half. You can also make the front half 1cm larger than the back half.
I divide the Stomach Circumference exactly in half:
86cm / 2 = 43cm
Other measurements I need for the calculations are Bottom Arc Front (190cm) and Bottom Arc Back (210cm).
As the result, the bottom circumference of the skirt is:
190cm + 210cm = 400cm
But there is no way the bottom circumference of the skirt should equal the bottom circumference of the petticoat, which is 400cm in our case. It will make the dress look as if it were stuffed with wadding. The skirt of the dress should be a little looser. It will look awful if pulled tight on the petticoat.
I will first calculate everything using the initial values and then add some looseness.
Let us calculate the flare for the front half of the skirt.
The front of the skirt features two side seam lines and two princess seam lines. Considering that a princess seam is two edges sewn together, there are six raw edges at the front of the skirt. I need to add a flare to each of them.
Here are the initial values for the calculations:
- Bottom Arc Front - 190cm,
- Stomach Width Front - 43cm.
190cm – 43cm = 147cm. This is the total amount of flare to be added to the front half of the skirt, which needs to be distributed between its six raw edges:
147cm / 6 = 24.5cm
I have decided to do the following:
- Add 24cm in the princess seams,
- And 25cm in the side seams.
Let us calculate the flare for the back half of the skirt.
There are two side seam lines, two princess seam lines, and one central seam at the back of the skirt. Considering that a princess seam is two edges sewn together and the central back seam does not imply a flare, there are six raw edges at the back of the skirt. I need to add a flare to each one.
Here are the initial values for the calculations:
- Bottom Arc Back - 210cm,
- Stomach Width Back - 43cm.
210cm – 43cm = 167cm. This is the total amount of flare to be added to the back of the skirt.
Since the side seam lines of the front and the back of the skirt need to have the same shape, they also need to have the same amount of flare – 25cm.
The part of the flare which falls upon the side seam lines of the back is:
25cm x 2 = 50cm
In this case, this is how much falls upon the princess seam lines at the back of the skirt:
(167cm – 50cm) / 4 ≈ 30cm.
In other words, here is the amount of flare added at the back of the skirt:
- 30cm in each princess seam,
- And 25cm in each side seam.
Apart from this, I need to leave some allowance for freedom of movement.
The skirt has a total of 12 edges, six at the front and six at the back (the central back seam is not taken into account), and I have determined the amount of flare along each of them.
Forty-five or fifty centimeters would make a sufficient and yet moderate allowance for freedom of movement. It would not form additional folds but simply allow the woman to walk freely in the skirt.
I will expand the skirt 4cm along each of the twelve edges.
4cm x 12 = 48cm. Such will be the total allowance for freedom of movement. And it is more than enough!
To sum it up, I need to add the following values to form the flare of the skirt starting 10cm below the waistline:
- 29cm in the side seams,
- 28cm in the front princess seams,
- 34cm in the back princess seams.
Knowing the lengths of princess seam lines and side seam lines of the front and the back of the skirt, I will draft the skirt directly on the fabric and add the desired amount of flare as calculated.
There is no need in any additional patterns!
The standard pattern enclosed with the course stops at the hip line. The remaining configuration of the skirt depends on your client's individual measurements. You can design something totally new, too.
As for me, it is time to draw the adjusted pattern on paper.