Drafting the trousers pattern (1/2)

Finding pants that perfectly fits our shapes is not an easy task. There are many morphologies and women and this is why, among ready-to-wear collections, there are more and more stretchy jeans and pants and very few classic trousers because it is virtually impossible to create a model that goes to everyone.

So, after a long and unsuccessful pants hunting, I started to wonder if I could not do it myself, even if I had to dive into geometry and mathematical formulas. The method I present here comes from the book of Teresa Gilewska, “Pattern Drafting, Volume 2”, method that I find simple and effective, or at least the one which has perfectly worked for me. By following this process, you can draft the basic pattern for high-waisted pants that are adjusted to your measurements. If you want a “sportswear” pant or a jean, there is another pattern presented here

Before starting to draw, arm yourself with the following:

  • a large sheet of paper (100cm X 120cm)
  • a long ruler (80 cm)
  • a French curve
  • a protractor
  • a calculator
  • a pencil and eraser
  • calm and patience

Carefully take your measurements:

  • Waist size
  • Hips size
  • Knee circumference
  • Desired ankle circumference
  • Leg length
  • Back waist length
  • Knee length
  • Height of hips

Get someone to help you. That “someone” will also be very useful when you will make adjustments. To have beautiful pants, one must already have friends.

Let’s begin the construction of the pants. The front and back pattern will be drawn side by side:

1. Draw the waist line 10 cm from the short edge of your sheet. Then draw all horizontal lines, parallel to the waist line, from one edge to another:
Hips line by taking into account the height of hips
Back waist line by taking into account the back waist length
Knee line by taking into account the knee length
Floor line by taking into account the leg length

1. Mark A on the waist line, 20 cm from the left long edge of the sheet. Calculate AB = ¼ of the hips size and draw two vertical lines from A and B (Figure 1).


2. On the back waist line, add DC to the left of the vertical line from A, where DC = 1/20 hips size – 1 cm.

3. On the bisector line for DCE (line that divides the angle into two equal angles), mark CF = 2.2 cm. Then draw a curve for DFE (Figure 2).


4. Calculate MB = (AB + CD) / 2 and mark M on the waist line. From M draw a vertical line that represents the crease. Write down the measurements AM and MB on the pattern, they will be needed for the construction of the back.

5. Calculate GH = knee circumference / 2 – 1 cm and divide the result between the two sides of the crease.

6. Calculate IJ = desired wingle circumference / 2 – 1 cm and divide the result between the two sides of the crease (Figure 3).


7. The back pattern will be drawn to the right of the front pattern. Mark BK = 15 cm and AB = KL. From K and L, draw two vertical lines at the waist line.

8. On the waist line mark a point M’ in order to have KM’ = MB and M’L = AM and then draw the back crease from M ‘. Add NO = 1/20 hips size + 2 cm (FIG. 4).


9. On the vertical line passing through O, measure 2 cm below the back waist line and place a point P.

10. On hips line, measure 3.5 cm to the left of the vertical line from K and place a point Q. Also mark 3.5 cm to the left of the vertical line from L and place another point R.

11. On the waistline mark SK = 1.5 cm.

12. Draw a short line, 2.5 cm above and parallel to the waist line.

13. Calculate ST = ¼ waist size + 2.5 cm and mark this measure from the point S to the extra line above the waist at the point T. Join TRNP points by a curve (Figure 5).


14. Calculate UV = knee circumference / 2 +1 cm and divide the result between the two sides of the crease.

15. Calculate WZ = Desired ankle circumference / 2 + 1 cm and divide the result between the two sides of the crease.

16. Join points placed on the vertical and horizontal lines by either curves or straight lines (Figure 6).


The construction of the pattern is partially completed. You will also need to add the waist darts and the ease. But as there were any more letters left in the alphabet I decided to continue the pattern in the next article.


66 thoughts on “Drafting the trousers pattern (1/2)”

  1. Thanks for your site, I visit here quite often – I love your tutorials and drawings.
    One question. How to you measure back waist length? From where to where on the body? Sitting or standing? I’ve tried to take measurements for drafting or altering trouser patterns often, but I come out with different values for this measurement every time!
    Thanks again, Penny

    • Hi Penny, you can read my post on how to take body measurements (the link is in this post). The back waist length is to be taken from the waist to the chair if you are sitting. I hope this helps

  2. I have been making jeans for a year or more now. And have made my patterns from existing pants. I really wish I could understand how you do this. I am much more of a visual person do you have a video of this tutorial? Or know where I can find?

    • Hi Eric, I’m afraid the 2D pattern drafting is all about drawings and calculations and less about videos. You really need to take on each step carrefully in order to avoid errors. It might seem painful but is is worth doing it

  3. Dear, It was very helpful,very simple I am new for swing I was trying some other and not understand how to make crotch or I mean not understand the measurement specially they put front with back but you make it separate.
    Best regards,

  4. I was desperately looking for this .Thanks a lot .I think this will come out brilliantly
    One suggestion – How to take measurement also could be included .Also it may be better if drafting of back and front is shown severalty for new comers

  5. Hi

    after cutting as per your measurements the hip size is showing smaller and waist too big

    could you give an example with measurements

    • Hi Sofy Mohan, what measurements did you exactly insert and what values did you obtain for hips and waist?

      • Yes i haven’t cut out the pattern because i notice you didn’t use the waist measurement at the waistline but kept a straight vertical line from hips to waist. I wish i can change it on my own accord but i’m too afraid i might mess up the position of the crease . Please if you would help me

        • I’m afraid it is not clear for me what you intend to do

  6. Thank you for this! It makes patternmaking look very easy.
    However, there is one thing that I do not understand: the corner of the waistseam and the centerback seam is not an 90 degrees angle. So, when sewn together, the waistline will not be a straight line but it will be a bit pointy. Is that how it should be?
    (sorry for my poor English, I am not a native…)

    • Hi Joanna, if you refer to point T, indeed there is no 90 degrees angle. However, knowing that TR is not exactly parrallel to the grain line, when you sew together the 2 legs, the fabric stretches a little bit and ST becomes a curve rather than a pointy angle.

  7. I’m confuse of how to measure the height of the hips and the back waist lenght

    • if you click on the link in the article, you might find the answer

  8. Thank u for this tutorial. It is very useful can’t wait to give a try.

  9. This is so clear, so detailed and so meticulous! Thank you…I am new to sewing (and maybe too old to pick up things quickly ), but this is crystal clear.I am now encouraged to try making pants. One small question…if one does not have a flat stomach is there a way to accommodate the belly?

    • Hi Janaki and thank you for your message, of course there are ways to accomodate the belly 🙂 but please make a test pants before cutting into the final fabric as pants are always experimental: instead of drawing AE line parallel to center front (M line), you need to draw it slantwise in order to get a larger AB

  10. Thanks for your tutorial Janaki. I wanted to know how you divide GH on both sides of the crease in Fig 3. They are not equally divided. Is it the same as AM:BM?

    • Hi Afia, actually you divide IJ equally and then you draw the perpendiculat till AB

  11. Thanks for your excellent drafting tutorial.

    Does UV and WZ measure equal on either side of crease line? Compared with GH and IJ, it doesn’t appear proportionate. Could you please clarify this.

    Nevertheless,Thanks for this draft!

    • UV could be not equal to WZ as knee and ankle circumference could not be the same

  12. Hi Janaki, what type of french curve do you need for this pattern? I have been looking around, but there seems to be many different shapes.
    Many thanks, Jayne

  13. I am a beginning sewer, but was a draftswoman for 30 years. Looking forward to sewing them up. My travel pants were bought from Eddie Bauer, on sale recently, and size 2 was actually larger than a size 10. So many clothes made in Vietnam without proper quality control. Thanks so much for clear, easy to read drafting instructions. I know these will fit properly.

  14. Hi dear.. May I know for the knee measurement back and front, such as : UV = knee circumference / 2 +1 cm… is it divide by 2 or 4 dear? I divide by 2 but got big knee since that it is almost to my waist measurement. Thank you

    • as you are building a half – pattern, you need to divide by 2. are you sure your knee measurement is correct? as a knee is rarely as large as the waist

    • actually you do not need to take crotch length for drafting this pattern, only back waist length

  15. Hi
    Thanks for making it so easy i just want to ask a que is how do u mark T how many inches it should b above from waist?

    • I am not sure as most of the time I see either back waist or crotch length which is the sum of back and front crotch depth

  16. Hello! Your Blog is great, I’m having a great time making my own patterns with your help, but right now I’m pretty stuck with this one. I’m hoping you’ll help me, how do I calculate the space between the hips line and the back waist length line? Is it the back waist length measurements taken from the waist line?

    • hello, you measure the back waist lenghts from the waist line to the chair you are sitting

  17. i am searching for the perfect pattern of pants..and i am happy to get this..would me show the 2D pattern to attach zipper and pockets of the pants( front zipper not the side one )

  18. Hi there,
    Many thanks for this. The crease line (M`) does not appear to be at the centre of UV (or WZ). Could you explain how the positioning across the crease is calculated for these two lines please? Thank you!

    • Hi Naomi, to fix the M line you need to calculate MB = (AB + CD) / 2 and then you know that KM’ = MB so you have your M line for the front and for the back pattern

  19. Hello there ,thank you for this very easy explanation.Before i measure the crotch line ,do I need to subtract the band width before drafting.say my crotch is 10inch,do i draft it as 8 on my pap art considering that I will be adding a band of 2 inch

    • Hello Taiwo, good question…of course this pattern is just the beginning, the basic slope, then you will need to alter it in order to set the final waist line and consider the band….so I suggest you to add the basic pattern with the crotch of 10 inch and then to draw a second pattern where you decide your waist line height and the width of your band. I hope that helps

  20. Hi, this is a really great tutorial and my pattern is looking really good, however, it seems the waist of my back pattern is smaller than the front. Is this correct? I followed your instructions to a t

    • hello ads, great to know you love the tutorial, however, the waist line front and back should be of the same length

  21. Pingback: Trouser – Siwain
  22. Thank you for this tutorial.
    I have a query regarding figure 6 , the back leg draft. I understand that the measurements for the knee and ankle are different, however it would appear from the picture that the measurements on either side of the creaseline are not equal. In your instructions no 14 and 15 you say to divide the result between the two sides of the creaseline. Should it be equal and if not how is it calculated.

    • hello, in the picture the creaseline might not seem in the middle but if you respect the indication, it should

  23. Thanks for this. I hope it works well.
    do I need to add seaming allowance when cutting the fabric?

  24. Hello, these are helpful aids for me as a Design, cutting and tailoring student beginner!

  25. Nice. Very well written. I need to sew for husband who has a longer rise than most recay to wear for men and more in the buttocks than ready to wear. Is there a different formula to drafting the crotch curve for men’s pants? Can you tell me this or point me to where I can find this information? I have been searching and just cannot find this. Thanks.

    • Hello Kay, unfortunately I do not know any blog expaining the men pattern so the safest thing to do is to buy the dedicated book

  26. Heyyy, thanks a lot ,this really helped but I did not understand from the step of how to construct MB so I will like for you to shed more light on it. thanks.. Chelsea

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