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Nov 01, 2023

How to alter a sewing pattern: Watch our video tutorial

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We earn a commission for products purchased through some links in this article.

Make every pattern perfectly work for you

We always aim to provide you with modern and easy-to-wear sewing patterns here at Prima, but sometimes you might want to alter a sewing pattern to make it more "you".

That's part of the beauty of learning how to sew and making your own clothes – you can make them totally personal to you. In our video, we take you through five brilliant hacks to alter your favourite sewing patterns, from lengthening and shortening trousers or a dress to adding a peplum to a skirt. You're guaranteed to use these sewing techniques time and time again.

You don't need many extra materials to alter your sewing patterns – all you'll need is some extra pattern paper or tracing paper and a Pattern Master, plus the usual scissors and tape measure you'd use for your sewing.

Watch our video to learn our tips for the easiest pattern hacks to update your favourite projects and refresh your wardrobe.

Happy stitching!

Tweak any pattern to accommodate your height. We’re using Prima Pattern June 2022 (Culotte Trouser) & March 2022 (Wrap Dress)

Step 1

Start by checking your required lengths. For trousers, measure your inside leg; measure from a comfortable point giving clearance for movement and sitting to hem required. For the dress, measure from the waistline to the hem you require.

Step 2

Most patterns have markings to show where lengthening and shortening can be done. However, if not you can add a slash line onto the pattern yourself. Using a ruler or Pattern Master, draw a perpendicular line through the front pattern piece about half-way down the pattern piece. Cut through this line.

Step 3

To shorten take the lower half of the pattern piece and overlap the upper piece by the amount you wish to reduce. The pattern pieces must remain in line with one another so check the grainline remains a continuous straight line.

Step 4

Tape the pieces together and check the side seams and inside leg (for trousers) or centre front/centre back (for dress). If these do not align, you need to gently taper them together by drawing a neat line running from the upper piece (at hip) to the lower piece (at hem). Keep these lines as straight as possible, no wonky angles! Now they are ready to cut.

Step 5

To lengthen your garment, you will need to add some paper by attaching it to the upper pattern piece and securing with tape. Grab your pen or pencil and extend the grainline onto the extra paper. Then mark the length you wish to increase the pattern piece by with a line parallel to the slash line. You can then line up your lower pattern piece at the extended length, ensuring the grainlines remain in line with one another. Tape down and follow step 4 for finishing.

Step 6

Repeat the process with the back pattern piece(s).

This is a fabulous way to modernise an existing pattern or lengthen a dress you would rather covered a little more. We’re using Prima Pattern July 2022 (Sun dress)

Step 1

Firstly, measure from your neck point at the shoulder the total length you require. Subtract the current pattern length from this to work out your peplum length; so, the required dress length – pattern dress length = peplum length.

Step 2

Measure the hem width on the original pattern piece you will be attaching the peplum to (remember to do this for front and back pieces).

Step 3

Draw a rectangle, 1 ½ to 2 times the width of the existing pattern hems by the additional length required.

Step 4

Cut this out as per the existing pattern pieces. For instance, for the sundress pattern it advises "cut 2 on fold", so add this same instruction to the peplum.

Step 5

Sew up the side seams as directed in the original instructions. Insert two rows of gathers around the top edge of peplum. Draw up these gathers to fit the lower edges of the dress and arrange them evenly.

Pin and stitch the top edge of the peplum to the lower edge of existing dress. Follow the pattern instructions to finish.

This is a fantastic way to create something unique by adding seams to mix and match florals or colour block your creations. We’re using Prima Pattern January 2022 (Blouson Tunic)

Step 1

Take the pattern pieces you wish to adapt; we chose to adapt the front/back and the sleeve. Using a ruler, draw a line through your pattern piece at the preferred section. In this case, the line is close to the hem, so echo the curved line of this hem. For the sleeve, add a straight perpendicular line to the grainline.

Step 2

Slash through the lines and using some pattern paper, tape a piece to each of the cut edges and add a seam allowance. For all Prima patterns, this should be 1.5cm.

Step 3

Once all the pattern pieces have a seam allowance, you can start to lay out your pieces for cutting.

TIP: We recommend sketching a version on paper before cutting out any fabric to make sure you are happy with how the garment is blocked.

This technique will ensure you can tweak a pattern to a shape you know really suits you. We’re using Prima Pattern April 2022 (Jersey Dress)

Step 1

Before starting this pattern hack, take your measuring tape and measure the neckline (excluding seam allowances) of the front and back pattern pieces. Then measure the length of the neck binding (excluding seam allowances). Make a note of these measurements for later.

Step 2

Taking the front pattern piece, draw in the shape you wish your new neckline to take. Measure the depth and width you have drawn and check you are happy with the shape and dimensions on your body. A minor change will make a big difference!

Step 3

Taking the back pattern piece, line up the shoulder seams and mark your new neck point on the shoulder seam of the back pattern piece. Draw in a new back neckline, making sure to drop the centre back neck point a little if needed. This should join the centre back at a right angle.

Step 4

Measure this new neckline (excluding seam allowances) and subtract the original pattern measurement. Add the difference to the binding length to ensure it fits correctly.

If you are adapting a pattern with facings at the neckline, you can exclude the points above concerning the neck binding, and instead make sure you echo the new necklines (including seam allowances) on the facing pattern pieces before cutting.

TIP: For creating soft curves, we recommend using a French Curve, available from all good haberdasheries.

Create an elasticated or puff sleeve to update your pattern or even a previous make! This is not a pattern hack per se, but it is an effective way to update your outfit that we think you will love. We’re using Prima Pattern May 2022 (Wrap Top)

No need to make any changes to the pattern here, but when it comes to finishing your sleeve hem, follow these instructions.

Step 1

Before starting this adaptation, grab your measuring tape and measure the circumference of your arm where the sleeve hem will sit. Keep this a little loose – there's nothing worse than elastic that's too tight. Make sure you can also get it over your hand comfortably.

Step 2

Take the sleeve hem, turn under 1cm and then 2cm, and press to hold. Pin and stitch around the hem leaving a 3cm opening on the underarm.

Step 3

Take your elastic (measured to the required length plus seam allowance) and, using a safety pin, thread it through the gap and around the hem, holding on to the end. Secure the ends together and then tuck the elastic inside the hem. Hand stitch the opening to secure.

Step 4

If using this technique for an existing creation unpick a 3cm gap in the hem at the underarm and follow step 3.

Do you love sewing? Share your creations with us by tagging @primamag in your pictures on Instagram!

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