Drafting Instructions – Basic Top Foundation

January 10, 2025

Welcome to the Free Basic Top Pattern Instructions. Here you’ll be able to find a step by step guide on how to draft your basic top pattern.

The Measurements

The first step of this free basic top pattern instructions is to look at what measurements are needed. Make sure to write them down on a piece of paper and that the tape is not too tight around your body. It’s also important to understand that it’s okay not to be super precise, as you’ll be able to modify the pattern during the prototyping phase.

I would advise you to take the measurements wearing your typical underwear. Also, this pattern is drafted as if both sides are symmetrical. If you know your body is very asymmetrical, draft this pattern for both sides and then put them together.

Nape to waist

Measured from the base of your neck, down to where you measure your waist circumference and going above the nipple.

Bust circumference

Measure the circumference of your bust, making sure the tape is not too tight and it’s over your bust apex.

Neck circumference

Measure around your neck and make sure the tape is sitting comfortably. In other words, how big you want the neckline to be.

Shoulder

Measure from the base of your neck along the shoulder until the shoulder bone.

Back width

Measure at the back, at the top of the armpit from side to side. The tape should be over the shoulder blades.

Chest

Measure at the front from armpit to armpit. The tape should be over your breasts and not over the nipples.

Waist circumference

Measure the circumference of your natural waist which normally is the thinest part of your torso. Just below the ribs.

Bust separation

Measure from one bust apex to the next one in a straight line.

Nape to bust

Measured from the base of your neck, down to your nipple, following the same path as with the Nape to Waist measurement.

The Basic Torso

Let’s start with the drawing steps for this free basic top pattern instructions This pattern has some standard measurements (like for the waist darts, the necklines, ease, etc.), but you’ll be able to adjust them during the first prototype.

Step 1 - The Structure

Step number one is to build the structure of our top foundation. We start at the top left and mark 0.

- 0-1: Nape to waist measurement + 2 cm
- 1-2: Half the bust circumference plus 5.5 cm (This is for standard darts but I’ll show you how to adjust it later)
- Finish drawing the rectangle
- Divide the structure: From the line 0-1 half way to 1-2. The front is on the right and the back is on the left

Step 2 - The Necklines

Once the main structure is ready, let’s draw the necklines.

0–4: 2cm down
0–5: Neck/5 – 0.2cm

Close the rectangle 0-4-5 and draw a diagonal line out of the rectangle that is 1.5cm long. With these points, you can now draw the back neckline (points: 4, diagonal, 5)

3–6: Neck/5 + 0.2cm
3–7: Neck/5 – 1.6cm

Close the rectangle 3-6-7 and draw a diagonal line out of the rectangle that is 2.5cm long. With these points, you can now draw the back neckline (points: 6, diagonal, 7)

Step 3 - The Main Lines

The next step is to define the main lines of the top

0–8: Nape to bust measurement – 1cm. This is the Bust Line
8–9: 3cm. This is the Underarm Line
4–10: Half the distance from points 4 to 9. This is the Back Line, so we will only mark it on the left side of the pattern
6–11: Half the distance from points 6 to 9 (or to the underarm line) + 2cm. This is the Chest Line so we will only mark it on the right side of the pattern
1–2: This is the Waist Line

Step 4 - The Armholes

Next step is to start drawing the armholes.

10–12: Half the Back measurement + 0.75cm. Draw a perpendicular line down to the underarm line

Draw a diagonal line from where the line crosses the underarm line that is 2.5cm

11–13: Half the Chest measurement + 2.5cm. Draw a perpendicular line down to the underarm line

Draw a diagonal line from where the line crosses the underarm line that is 3cm

Step 5 - The Shoulders

We are ready to finish building the shoulders and the armholes!

0–14: One third of the distance 4-10 plus 1.5cm
6–15: 0.5 cm above the neckline
14–16: The distance 10-12 + 2.5cm. This is standard ease that takes into account the shoulder dart. It can be corrected later
15–17: Distance 11-13 + 4.25cm. This is also standard ease that depends on the dart

Now that we have all the lines, draw the back shoulder (from 5 to 16), the back armhole (16 to 12 to the diagonal and to the centre of the structure) with a curve. If you have a french curve it will be easier to draw. Then the front curve (from the middle to the diagonal, to 13 and to 17) also with a curve. And finally the front shoulder (from 17 to 7)

Step 6 - The Shoulder Darts

This pattern has a shoulder dart at the front and at the back, let’s draw them:

Back:

The start of the dart is measured from 16 to the left along the shoulder and it’s shoulder/2 plus 0.5cm
The dart is 1.5cm
To find the length, draw a perpendicular line from the shoulder until 3cm above the back line

Front:

The start of the dart is measured from 17 to the right along the shoulder and it’s shoulder/2 plus 0.5cm
The shoulder length should be the same as for the back shoulder, the rest should be the dart
The dart goes down to the bust line and to find the specific point, add half the bust separation from the line 3 – 2

Step 4 - The Waist Darts

To finish the pattern we’ll have to lower the front waistline to account for the chest. I will be using a standard measurement but feel free to lower it more if you have more prominent breasts.

Lower 2 by 1,25cm (standard measurement) and mark “New 2”
Draw a line from 1 to New two and measure how long it is

Now it’s time to add the waist darts. For it, we’ll have to use a little formula:

(Distance: 1 to New 2) – (Waist + 4cm)/2 = a

The “a” measurement shows us how much we have to reduce at the waist (with ease included) to shape the top. Every dart will reduce the following:

Back dart: Reduce 33% of measurement “a”
Side seam: Reduce 26% of the measurement “a”
Front dart: Reduce from measurement “a” 27% to the left and 14% to the right

And just like that you completed the free basic top pattern instructions and you have your first basic top pattern! If you want to modify the pattern you can take a look at other patterns.

I also made a video showing the step by step instructions, go take a look if you want!

Once you have the foundations, it’s time to play around and change the necklines, add volume, change the opening, play with the seams or add any details you’ve ever dreamed of. This are the perfect foundations for dress designs, so the world is your oyster!

If you want to know more about how to modify the foundations check the tops 101 page or take a look at the free pattern instructions.

If you want to have a handy summary of all the top foundations and the instructions on how to change from one to another plus a pattern organiser and a pattern contouring cheat sheet, I have you covered.

Head to my shop by clicking the image on the right and get it now!