Lengthening or shortening the rise (crotch) of shorts or trousers (pants for my US friends) is easy enough to do with a bit of slashing and spreading of your pattern. That actually sounds much more dramatic than it is.

Having a few pattern adjustments options in your sewing tool box will always be handy as we are all different shapes and sizes, tall and short, or you might want to move the waistline for aesthetic reasons. 

As with most pattern alterations, think about where you need the extra fabric. And vice-versa remove fabric where you don’t need it. If you need more fabric to go over your bum, that’s where you add it. If you have an upsetting fold of fabric at the front rise , that’s where you don’t need it!

This alteration may be needed on the front rise or the back rise, or possibly both. And you may still need to make other alterations to your trouser pattern.

I’ve got 2 methods to alter the Rise (crotch length) of trousers to share with you. 

How to alter a Trouser Rise (crotch) – This will show  you how to alter a trouser rise without changing the side seam length. It can be done on the front or the back rise or both of the rises.

Long/short Torso Adjustment – The second method is a useful pattern alteration for those with a longer or shorter torso and shows how to alter both the front and back rise (crotch length) and the side seam length.

How do you know if you should adjust the Rise?

IF THE RISE IS TOO LONG – it’ll all be hanging too low and looks saggy (lovely) with excess fabric that you want to pinch out, you might even feel the need to pull them up all the time to make the rise sit comfortably, but then the trouser sits too high at the waist. 

IF THE RISE IS TOO SHORT – your trousers will be riding up uncomfortably high and you’ll be trying to pull the area down, the fabric may be pulling and creating drag lines. The waist won’t be sitting in the correct position and you’ll feel like you want to pull them up. 

This is quite a common alteration on the back rise. You’ll feel that it just isn’t long enough and too short over the seat area, and the trousers may be pulling downwards at the centre of the waist especially when sitting down. It’s an easy fix – you just need a bit more fabric to go over your bum.

Learn how to adjust the Rise of a trouser pattern

Tools

• A copy of your trouser or shorts pattern (it’s best practise to keep the original)
• ruler
• pencil
• tape
• Paper

Toile Time

Hopefully you’ve made a toile. That will give you a lot of information on the fit of your trousers.

• Make sure that the waist and hips are not too tight, a tight garment will ride upwards and not sit correctly on your body.
• Also take care not to overfit your garments, it’s usual to have some wrinkles as you need to be able to move and sit down.
• Pop your Toile on with the waistline sitting where it should be – keep in mind not all trousers are designed to sit at the natural waistline. 
• Pin or cut the toile to establish the amount you need to add/subtract from your rise. If I’m honest it’ll be a little bit of guesswork as it’s not easy to cut and pin a toile on yourself, be prepared to pull it on and off a few times but it will give you a good idea of how much to add to your pattern and you can refine it if you need too. 

How to Alter a Trouser or Shorts Rise

Rise is too Long – Pin the excess wedge of fabric on your toile at the centre and reducing to nothing at the side seams.

Rise is too short – Slash the toile open from the centre to the side seam. Let the toile open as much as it needs, pin some fabric behind to establish how much you’ll need to alter the rise. (You may be able to just measure from the top of your trouser to where it should sit on your body but often you’ll need to slash the toile open).

How to Alter For a longer or shorter Torso

Rise is too Long – Pin the excess wedge of fabric, try to keep it an even amount, on your toile all around the body. 

Rise is too short – You may be able to just measure from the top of your trouser to where it should sit on your body but often you’ll need to slash the toile open. Cut all the way through the toile and pin some fabric behind to help establish how much you’ll need to alter the rise.

Adjust the rise on a trouser pattern (without touching the side seam).

You can just alter the FRONT Rise or the BACK rise, or both rises using this method.

• Using a copy of your pattern piece mark the seam allowances so you know where the stitch lines are.
• Draw a lengthen/shorten line across the pattern through the Rise, ensure it is perpendicular to the grain line. I prefer to do this so it intersects the rise seam on a straighter section rather than the curve.
• Cut along the line, starting at the RISE seam and cut UP TO the side seam stitch line but NOT through it. Cutting from OUTSIDE of the pattern, cut through the seam allowance and up to the same point on the stitch line, leaving a 2-3mm hinge of paper. 
• *If you hinge your pattern from the outside edge of the pattern instead of the stitch line, your seam increases in length and then your pattern won’t fit back together properly.

To Lengthen the Rise Seam

• Place some paper behind your pattern pieces and tape the lower section of the pattern securely in place.
• At the Rise stitch line, mark the amount you need to increase the rise by above the lower pattern piece.
• Pivot the top pattern piece upwards from the hinge to add the extra amount and tape in place. 
• Redraw seam lines to give yourself a smooth line, and also redraw the grainline.
• THE CHAIN EFFECT – remember you may need to alter any other pattern pieces affected such as facings & fly patterns

To Shorten the Rise Seam

• Place some paper behind your pattern pieces and tape the lower section of the pattern securely in place.
• Mark the amount you need to reduce the rise by ON the lower pattern piece.
• Pivot the top pattern piece downwards from the hinge, overlapping the pattern pieces and tape in place. 
• Redraw seam lines to give yourself a smooth line, and also redraw the grainline.
• THE CHAIN EFFECT – remember you may need to alter any other pattern pieces affected such as facings & fly patterns

Long/Short Torso Adjustment

To adjust the Front Rise, Back Rise and the side seams of your shorts or trousers.

Use to lengthen the Front Rise, Back Rise and Side Seams 

• Using a copy of your pattern piece mark the seam allowances so you know where the stitch lines are.
• Draw a lengthen/shorten line across the pattern through the Rise, ensure it is perpendicular to the grain line. I prefer to do this so it intersects the rise seam on a straighter section rather than the curve.
• Cut all the way along the line.
• Place some paper behind your pattern pieces. Anchor the lower section of the pattern with tape.
• Extend the grain line upwards. 
• Draw a second parallel line above the your shorten/lengthen line the amount you need to lengthen the rise by. 
• Tape the upper portion of your pattern to the new line, matching up the grainline. 
• Redraw your seam line so they are a smooth line, and also redraw the grainline.
• THE CHAIN EFFECT – If you have a pocket bag, or other pattern pieces such as facings or Fly zips, remember you may need to alter them too. 

To shorten the Front Rise, Back Rise and Side Seams 

• Using a copy of your pattern piece mark the seam allowances so you know where the stitch lines are.
• Draw a lengthen/shorten line across the pattern through the Rise, ensure it is perpendicular to the grain line. I prefer to do this so it intersects the rise seam on a straighter section rather than the curve.
• Draw a second parallel line below it the amount you’d like to reduce the rise by.
• Cut all the way along the first line.
• Overlap the pattern pieces to reduce the rises and tape the pattern matching up the grainline. 
• If necessary, redraw your seam line so they are a smooth line, and also redraw the grainline.
• THE CHAIN EFFECT – If you have a side seam pocket I’d suggest remarking the pocket position to maintain the original pocket mouth opening size or you may find your hand doesn’t fit. You may need to alter other pattern pieces too. 

As with all pattern alterations, check when you’ve finished that your pattern seams still match and are the same length, they run smoothly and test your finished alterations with another toile before cutting into your good fabric.

All done and now you know How Adjust the Rise on a pattern for perfectly fitting trousers! Mrs M x