22 June 2022

Fitting Coralie

Tilly and the Buttons - fitting Coralie swimwear

Making the Coralie swimwear and need a little extra help getting the fit just right? Well, you've come to the right place! This post will cover the most common fitting adjustments you might want to consider for your Coralie. 

The Coralie swimwear, designed in collaboration with Hannah from Evie la Lùve, is a simple-to-sew, versatile swimwear pattern with multiple versions to choose from. Oh and did we mention it’s got ruffles too?! With so many gorgeous variations to sew we best get cracking!

Tilly and the Buttons - fitting Coralie swimwear

Our bodies are all wonderfully different and part of the joy of making our own clothes, lingerie and swimwear is that we can customise them completely to our shape and not have to settle with something that "kinda fits" bought from a shop. As with all sewing patterns, to get a perfect fit on the Coralie pattern, you may find you need to tweak the pattern a little bit before cutting out your fabric.

For best results, we recommend making a test swimsuit or bikini – AKA a “toile” – first before sewing in any special or expensive fabrics to check size and fit. It’s super important when making your toile that you use a fabric that has the same amount of stretch and recovery in both directions as the fabric you plan to make your final swimwear from. If it has a different stretch percentage, unfortunately it’s almost pointless making a test garment as it will fit differently. So make sure the stretch percentage is the same before you start, to save wasting your time and fabric! The fabric you use needs to have at least 50% stretch both widthways and lengthways. (Check out the supplies section in the online workshop for how to measure stretch percentage.)

In this post we’re going to cover:

Choosing your size
Lengthening or shortening pattern pieces
How to combine pattern sizes for different bust, waist and hip measurements
Full bust adjustment
Fixing a gaping seam
Adjusting the leg height
A quick fix for straps that are too long

Tilly and the Buttons - fitting Coralie swimwear


How do I choose my sewing pattern size?

Taking accurate measurements is the first step in making sure that your swimwear will fit. The three measurements you will need to determine your size are your bust, waist and hip measurements.

Using a flexible tape measure, find the circumference of your:

Bust – the fullest part of your bust, ie. around your nipples
Waist – the narrowest point around your middle, where you bend at the side
Hips – the fullest part of your bum (not around your hip bones, as the name suggests, which is higher up)

Check the tape measure is sitting level with the floor all the way around. It can help to turn to the side and look in a mirror to check.


Circle your measurements on the ‘Body Measurements’ chart in the pattern instructions. If your measurement falls between a size (for example, if your bust is 39in rather than 38in or 40in), it’s better to choose the larger size as you can take the swimwear in more easily than you can let it out.

If your measurements fall into one size on the body measurements chart, that is your size. Take a look at the size key on the pattern sheets and find the corresponding size line. Each size has its own solid or dashed line to make it easy to spot and help you follow it easily.

If your bust, waist and hip measurements fall into different sizes, do not fear! Sewing our own clothes means we can make gorgeous garments that fit our beautifully unique bodies. Yay! You can join up different size lines at to create a garment that fits your unique body measurements perfectly. See ‘How to combine pattern sizes’ below for more details.

But first, before you combine pattern sizes you might want to consider… 


How do I lengthen or shorten a sewing pattern?

This is a common alteration you may find you are consistently doing with your other sewing projects, and something you may find you need to do with the Coralie swimsuit or bikini. Unlike most dressmaking projects, as a swimsuit or bikini is designed for fabric that stretches lengthwise (as well as widthwise), the pattern piece should be shorter than your body and stretch to fit you, so you’ll need to lengthen or shorten less than you usually would to account for the "negative ease" in the pattern.

If you have a particularly long or short torso, you may want to go ahead and make some adjustments to the length before you cut into your fabrics, but you won’t know for sure until you’ve made your practice swimsuit or bikini. If you find you are getting a lot of horizontal wrinkles across the bikini top, bottoms or swimsuit, you may want to take out some length. If the swimsuit is sitting too low for comfort at the neckline, or you feel like in order for the neckline to be in the right place you are getting a wedgie (ouch!), then you will need to add some length in.

We’ve added two sets of lengthen/shorten lines to the Front and Back pattern pieces – one set around the bust or bikini top, and one around the hips or bikini bottoms. Even if you’re making the one piece swimsuit, it’s best to use both sets of lines to lengthen or shorten your pattern, splitting up the length added or subtracted between them.

How to lengthen the pattern pieces

The first thing you need to do is work out how much length you need to add in. As this pattern stretches to fit your body, bear in mind that if you added in, for example, an extra 5cm (2in) of fabric, this would stretch and mean you’ve added more than 5cm (2in). The amount the fabric will stretch depends on your fabric, your height and torso length, but a good general rule here is the fabric will stretch around 10%.

So if, for example, you want to add in 5cm (2in), you would only need to add in 4.5cm (1 3/4in) to the pattern, because the fabric will stretch the extra 10% needed.


On the Front pattern piece, cut along the top line on one set of lengthen/shorten lines (one set is around the bust, the other around the hips). On a new piece of paper, draw a horizontal line near the top that’s at least as long as the width of the pattern piece (shown in pink above). Draw a line underneath that is half the measurement you want to add into the overall length (again, shown in pink above) – that’s half of the amount you need to add to the pattern piece taking the 10% negative ease reduction we just covered into account.

Take the top part of the swimsuit pattern piece and line it up with the top line – stick this in place.

Extend the centre front line (labelled with the ‘Place on fold’ arrow) down vertically with a ruler – this will be the line you match the rest of the pattern pieces to (this is drawn in green above).

Take the lower part of the pattern and stick the top edge to the lower horizontal line you drew on the paper, lining up the centre front with the new vertical line you just drew.

Repeat with the lower set of lengthen/shorten lines (the ones near the hip).

Draw in a new side seam (drawn in green above) – you may need to even this out depending on how much you’ve added in.

Make the same adjustment to the Back pattern piece, as well as the shelf bra if you’re adding it to the swimsuit, making the side seams the same length and shape.

You can lengthen the straps too, using the lengthen/shorten lines on the neckline binding pattern piece. How much you lengthen by can be a bit of trial and error, but you have the stretch allowance in the fabric to help.

How to shorten the pattern pieces

First, work out how much length you want to remove from the pattern pieces. On your test garment, pinch out the excess fabric and measure this, without stretching the fabric. It will probably be at least 10% less than what you would usually remove from a top pattern.

Split the amount you want to shorten the pattern piece by in two. For example, if you want to remove 5cm (2in) across the whole pattern piece (swimsuit), remove 2.5cm (1in) at each set of lengthen/shorten lines. 

On the Front pattern piece, draw a horizontal line (drawn in pink above) above one of the sets of lengthen/shorten lines (one set is around the bust, the other around the hips), the distance between the two lines being half the amount you want to shorten the whole pattern by. Cut along the lengthen/shorten line.


Overlap the pattern pieces so the cut edge lines up with the new line you just drew, and stick in place, making sure the centre front (labelled with the ‘Place on fold’ arrow) is still a continuous straight line.

Repeat with the lower set of lengthen/shorten lines (the ones near the hip).

Redraw the side seam to smooth it out (drawn in green above).

Make the same adjustment to the Back pattern piece, as well as the shelf bra if you’re adding it to the swimsuit, making the side seams the same length and shape.

You can shorten the straps too, using the lengthen/shorten lines on the neckline binding pattern piece. Again, how much you shorten by can be a bit of trial and error, but you have the stretch allowance in the fabric to help. If they do end up too long on your final garment, see the last part of this module!

How do I combine different pattern sizes?

When you take your measurements and compare them to the size chart, you may find your bust, waist and hip measurements fit into two, or maybe even three, different sizes. It’s really easy to combine sizes to customise the pattern to your body measurements, rather than just picking the size closest to your measurements and hoping for the best.

If you are making the bikini top and low rise bottoms, you can choose the top size according to your bust measurement and the bottoms size according to your hip measurement independently, ignoring your waist measurement. If you are making the high waist bikini bottoms or one piece swimsuit however, you will need to take all three measurements into account for your best fit, and if your measurements fall into different sizes you will need to combine them as outlined below.


 On the Front pattern piece, draw in a new side seam joining up the lines in your size at the bust, waist and hip, using the three notches on the side seam as a guide. To create a smooth, curved line, use a pattern master or French curve if you have one, otherwise you can freehand it. The diagram above shows an example combining size 4 bust, size 5 waist and size 6 hips.

Once you are happy with your side seam, trace or cut the same line on the Back pattern piece, using your altered Front piece as a template. Make the same change on the shelf bra if you’re adding it to the swimsuit.

How do I fix a gaping seam?

If you are experiencing any gaping anywhere on your swimsuit, for example, along the underarm edge at the front or along the back leg opening, this is a simple fix for the next time you make it – or if you can summon the will to unpick it! Simply apply more tension on the elastic when you sew these areas on your next swimsuit or bikini and this will help it to hug your body more closely.

Another thing you can do to help fix a gaping underarm – as well as to pull in the back opening if it feels too loose on you – is to add in an elasticated back tie. Take a look at the dedicated module on this in the workshop.

How do I make a Full Bust Adjustment?

Blending between different sizes for your bust, waist and hip measurements is a great way to customise your suit to your body. However, if after you’ve made your test garment and you find your suit is generally fitting well but is too tight over your bust or you are getting excess fabric that looks like you could pinch out a dart from the under arm edge to the bust, you could try doing a full bust adjustment – or “FBA” for short.

It’s important to note that a full bust adjustment on a swimsuit isn’t an exact science as it isn’t drafted to a particular “cup size”. A large factor in determining the fit between the full bust and high bust will be the amount of stretch and recovery in the fabric that you have chosen. Stretchier fabric is going to have more flexibility to fit a wider range of bust sizes. So determining how much to add will be a bit of trial and error – you may want to start with 75-90% of what you would usually add to a pattern if you regularly do FBAs on stretch garments with no bust seams or darts (such as a t-shirt).


Swimsuit version: Cut the Front pattern piece along the cut line for the bikini top so that you are only altering the top section.

Bikini version: Cut out the Front bikini top pattern piece.

 

On your test garment, mark where your bust point is and transfer this to your pattern. This will be a slightly different place for everyone (shown by the pink dot in the example above).

Draw a line from here straight across to the side seam, then draw a straight line from the underarm edge to the bust point, and then from the bust point straight down to the bottom edge (waistline cut edge for swimsuit adjustment, bikini band seam for bikini top). Cut along the lines.

Separate the pieces by half of the extra volume needed (half as it accounts for half of the Front), keeping the cut away section at an even distance all the way down from the bust point to the lower edge. Make sure the underarm edges are meeting and the two cut away sections are meeting at the bust point. Stick this all in place on a new piece of paper.

Level off the pattern piece across to the centre front (this is drawn in green above).

Bikini version: Mark a point along the lower edge (underbust seam) that is the same width in from the side seam as the amount you added in at the bust, and taper the side seam into this point (drawn in green above). This will remove the extra volume added at the waist that you don’t need, but keep the volume you want to add in at the bust.

Even out the new underarm seam to create a smooth line (also drawn in green above).

Swimsuit version: Line up the upper and lower parts of the front pattern piece along the new waistline.

Draw in a new side seam, tapering it to where it meets the waist line (drawn in green above). Don’t “split the difference” here – you need to remove the extra volume from the waist as you only want it at the bust.

Even out the new underarm seam to create a smooth line (also drawn in green above).

That’s the Front pattern piece dealt with, but now the back pattern piece will now be too short to match the front at the side seam. Here you have a couple of options:

1. You can simply stretch the back as you sew it to the bikini top or top section of the swimsuit, so the two lengths meet – this will create some gathers on the front that may still be visible when worn, depending on how much extra volume has been added.

2. Or you can add the length needed into the back pattern piece, as shown in the diagram below.

For the shelf bra: If you are adding the shelf bra to the swimsuit, alter it by tracing off the same shape as the top part of the altered Front piece, and add a 10mm (3/8in) elastic allowance to the bottom edge.

Can I adjust the leg height?

The Coralie pattern has a mid-cut leg, but this is really simple to alter if you prefer a different fit.


Raising the leg height

To raise the leg height, for less coverage than the existing pattern, simply mark the height you wish to raise this to at the side seams on the Front and Back pattern pieces and draw a new leg opening, tapering into the existing leg opening. 

Make sure you remove the same length on both pieces and check that when you overlap the pattern pieces as they will be sewn (overlapping the seam allowances), they create a smooth curve from the front to the back.


Lowering the leg height

To lower the leg height, stick some extra pattern paper behind the pattern pieces at the leg openings if you’ve already cut the pattern out. Extend the side seams down by continuing the line by the length you wish to add on both the Front and Back pattern pieces. Draw a new leg opening from this point, tapering into the existing leg opening. 

Make sure you add an even length to both Front and Back and, when you overlap the pattern pieces as they will be sewn (overlapping the seam allowances), they create a smooth curve from the front to the back.

What should I do if the straps end up too long?

In the lengthening and shortening section, I explained how to add or subtract length from the straps before you’ve cut out your fabric. But what if you’ve finished your swimsuit and then discover the straps are too long? A quick fix is to simply pinch the length out at the shoulder and sew with a straight stitch across this part of the strap to create a seam. Go over this back and forth a few times to make sure it’s nice and secure before chopping off the excess.

Next time you make the swimsuit remember to remove the length you’ve taken away!

These are the most common adjustments you may (or may not!) need to make to get a swimsuit or bikini that fits you perfectly. Get a fit that you’re happy with, and don’t stress over it too much!

For LOTS more help with your swimwear stitching adventures, sign up for our new online workshop:

LEARN TO SEW SWIMWEAR


We love seeing your finished makes and progress shots. Tag us on Instagram @TillyButtons and @EvieLaLuve using the hashtag #SewingCoralie to share your gorgeous makes with us!

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Author: Hannah Bullivant
Illustrations: Frances Buddery
Models: Alice-May Bermingham & Abi Ogunbambi
Photographer: Jane Looker
MUAH: The Bridal Stylists