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.

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.


17 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?

  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

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