Français
How to adjust your bra with 2 different cups sizes

How to adjust your bra with 2 different cups sizes

There is no scoop here, we all have a difference of size between our two breasts. Nobody is 100% symmetrical, and, in a way, this makes us even more unique 🙂

For some of us, this difference of size is even more contrasted, naturally, or after life events.You are part of those women? So you do know how difficult it is to find a bra that fits you perfectly… Well, this article is for you!!

We explain to you how to adjust, altern, your pattern to YOUR morphology.

To make it easier (for us), we will take for examples 3 of our bra models with different types of construction, because this will give you a chance to do it on any bra sewing pattern later 👌

No more drama with a breath in the good size, when the other one is too tight, or in the opposite, is drowning in the cup.

Of course, the first thing to know is the exact size of your breast. At the end, this is the most difficult part, as we know that 80% of women, even those with the identical size of cups, are wrong about what size they need!

We advise you to go in store and seek advice from a saleswoman, and above all, do some fitting test with several sizes AND different kinds of shape… until you feel what is the best for you.


For this tutorial, let's imagine that :

Your right side cup corresponds to M pattern size,

your left side cup corresponds to our L patterns size,

and your band to our M pattern size.


Are you ready ? Let's go !

  1. Smoothie bra : cups separated by a bridge
  2. Cherylada bra : cups with common seam on middle front
  3. Curaçao bra : cups with two common seams on middle front)
  4. What about the elastics lenghts ?

1. Smoothie bra : cups separated by a bridge

transform two sizes bra On your graded Smoothie sewing pattern, highlight sizes M and L, for pieces n°1, 2 and 3 composing the cup:

- Neckline
- Bottom cup
- Bottom cup Lining
adjust bra pattern Then, duplicate each piece separately in symmetry, in order to obtain:

- Size M for right cup.
- Size L for left cup.

Here, Neckline piece.
how to adjust bra pattern two different sizes Do the same for Bottom cup and Bottom cup Lining pieces.
underbust bra pattern right side Now, let's move to the underbust (piece n°4) :

On the wing of right side: link the line of cup size M, to the middle back line in size M.
underbust bra pattern left side And, and the wing of the left side:

Link the line of cup in size L, to the middle back line in size M.

And here is the result of the pattern alteration!

Go to paragraph 4 to know which length of elastic you need to use to get a great 100% custom bra!

transformer patron dos bandista piece n°4


2. Cherylada bra : cups with common seam on middle front

bra pattern alteration On your Cherylada graded sewing pattern, highlight sizes M and L on the cup piece.
bra pattern alteration two cups sizes Then, duplicate each piece separately in symmetry, in order to obtain:

- Size M for right cup.
- Size L for left cup.

Superimpose the line of middle front, by aligning the bottom, at underbust line.
pattern making bra As you can see, there is a difference of height between the two middle front.

To adjust this, draw new lines by starting by the highest point of neckline, until the point in the middle of this difference of height.
adjust two sizes cups bra Draw these new lines that will allow you to have the same length of middle front line between the two cups.
adjust two sizes backband bra Now, let’s move to the wing (piece n°2):
For right side: link the line of cup in size M, to the middle back line in size M.
adjust two sizes backwing bra For left side: link the line of cup in size L, to the line of middle back in size M.

And here is the result of the pattern alteration!

Go to paragraph 4 to know which length of elastic you need to use to get a great 100% custom bra!

transformer patron dos bandista piece n°4


3. Curaçao bra : cups with two common seams on middle front

cups with two yokes On your Curaçao graded sewing pattern, highlight sizes M and L, for pieces n°1, 2 and 3 composing the cup:

- Upper Cup
- Side Bottom Cup
- Middle Bottom Cup
adjust two bra sizes Then, duplicate each piece, separately in symmetry, in order to obtain:
- Size M for right cup
- Size L for left cup
lingerie pattern alterations Superimpose the lines of middle front of the two Upper Cups (piece n°1), by aligning them at the the bottom, at horizontal seam.

There is a small difference of height between the two Upper Cups.

To adjust this, draw a new line by starting by the neckline of the smallest size, until the arriving of the biggest one.
lingerie bra alterations Do the same thing for the middle bottom cups (piece n°2), except that this time, the difference of height is bigger.

To avoid creating some “imbalance” in the sewing pattern, superimpose the two pieces at the middle from one another.
And, draw news lines at the top and the bottom to equalize the differences of height.
lingerie pattern alterations cups Now, let’s move to the wing (piece n°4):

For left side: link the line of cup in size L, to the line of middle back in size M.
customize bra cups alteration Pour le côté gauche : relie la ligne du bonnet taille L, à la ligne de milieu dos taille M

And here is the result of the pattern alteration!

Go to paragraph 4 to know which length of elastic you need to use to get a great 100% custom bra!

transformer patron dos bandista piece n°4


4. What about the elastics lenghts ?

One more last thing to do (yes! yes! 😅): some maths to calculate the length of elastic that you will need.

For this, have a look at the chart of the tutorial of your sewing pattern:

- Underbust elastic:

Just take the measurement of underbust from measurement chart (for this example, the length of elastic is in size M).

- Right side underarm elastic:

In this example, the size of right cup is the same as the size of wing. So just take the measurement of the measurement chart (for this example, the length of elastic is in size M)**

- Left side underarm elastic:

In this example, the size of left cup is one size bigger than the size of wing:

Take the measurement of the underarm from the size of the cup (here the length of elastic is in size L), and take off 2cm (3/4 in) to this measurement (which is the difference of measurement between two size).


We hope you enjoyed this tutorial and that it inspired you for future creations👙

Do not hesitate to take a look at our Sewing tips and our Blog articles if you want to learn new techniques

And of course, if you have any doubts, don't hesitate to contact us :

contact@fitiyoo.com