How to adjust a trouser pattern

Hi! This is a tutorial on how to adjust a trouser pattern to your measurements. For example, I’ll use my measurements and my recent trouser pattern I released called Inès. Here is the link if you want to check it out ( CLICK ) This simple technique will work with any oversized/ loose fitted trousers with darts or pleats.

The idea is to adjust the waistband to your measurements while leaving the trouser pattern as it is. If your waist is slightly smaller than the pattern you can adjust the waistband pattern and include extra fabric in darts and pleats. If your waist is slightly bigger than the pattern you can adjust the waistband pattern and take out extra fabric from darts and pleats.

So how to adjust a trouser pattern to your waist measurement?

First, measure your waist ( mine is 72cm and I’m wearing size UK 8 / EU 36 / US 4/ AU 8 which fits me spot-on). Your trouser waistband pattern is divided into 3 pieces left, right and back panel. Now, take your waist measurement ( in my case 72cm) and divide it in half. That will give you a measurement for front and back ( in my case 36cm ). For the back pattern measurement, we only need to add 2cm seam allowance and that’s it. Your own back waistband panel measurement ( in my case 38cm ).

Then we divide our front measurement in half ( 36cm in my case as mentioned above will be 18cm per side ). Now as this pattern has a button fastening we need to add some extra cm for the waistband to overlap. The panel which has a button must be a little bit longer, in this case, it’s a left panel.

Take half of your front measurement ( in my case 18cm ) and add +4cm of extra overlap +2cm of the seam allowance. The total amount will be the width of your right panel ( in my case 24cm). Then take half of your front measurement ( in my case 18cm ) and add +8cm of extra overlap +2cm of the seam allowance. The total amount will be the width of your left panel ( in my case 28cm).

Do I also need to adjust the trouser pattern?

Not really, when you select your own size and your waist is slightly smaller or bigger there shouldn’t be an issue as you can add or remove any extra millimetres to darts and pleats on the trousers. The problem begins when your waist measurement is significantly bigger than the pattern. In that case, you’ll need to add some extra cm to trousers otherwise you might now have enough material to create darts and pleats.