How To Lengthen A Trouser/Pants Pattern

Found the perfect trouser pattern but it needs lengthening ? Being 5’8” this is something I always encounter. I’m going to show you how to lengthen a trouser pattern using my Bramber Trousers. They have a turn-up hem so you can’t just add a few inches to the hem if you wish to keep this feature.

Although I’m using this specific pattern, the principal in the same for any trouser pattern. If you have a pattern with a plain hem and just want to lengthen them a little (3cm or 1.5 inches max), then you can just add that to the bottom of the trousers and you should be fine. But if you need to lengthen the pattern by more than that, or you also have a pattern with a turn-up hem, then you should follow the process outlined below.

If you have a pattern with a twisted side seam (like our Tidebrook Trousers) then take a look at our other blog post specifically about that.

The Bramber Trousers are designed to be cropped and drafted for a 5’4” height. I’m going to add in an extra to 8cm or 3.25” into the leg length in this demo, whilst maintaining the turn -up feature.

This the front trouser pattern for the Bramber trousers. Note the wobbly bit at the hem, this allows for you to make the turn up at the hem without distorting the bottom of the trousers.

To start, lay the pattern piece on the fabric as economically as possible whilst ensuring the grain line is following the straight grain.

Next , secure the top of the trouser pattern to your fabric with pins or weights. Cut through the lengthen/shorten line carefully.

Next, move the bottom piece away from the top by the amount you wish to increase the leg length by, 8cm in this instance.

Ensure the measurement is the same at both ends. Pin your pattern into place.

Lay a ruler along the side seam edge of you pattern so it blends the two pieces smoothly. This may mean you need to fold back a small piece of the lower trouser piece.

Use a chalk or erasable pen to mark your new side seam line connecting to two pieces.

Here’s a further out view.

Do the same for the inside leg seam. Again, you may need to fold back a small part of the lower leg pattern to achieve a straight line.

You should be left with something that looks a bit like this. This is basically it! Do the same for the back leg pattern piece, ensuring you insert the same amount. Then carefully cut out following your drawn lines.

Want a plain hem rather than a turn up? Simply cut your fabric at the middle fold line on your pattern. This will leave a 3.5cm or 1.25” hem allowance to turn under for your plain hem.

I thought I’d add this in as, again it’s a very simple thing to do but gives you another ‘look’ to your trousers. I wanted to make this pattern as customisable as possible to give the purchaser lots of options. Once you’ve got your perfect fit you can then make several different looking pairs with the same pattern.

Sussex Seamstress is an independent pattern maker, based in Sussex, UK.

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