2 February 2013

How to Select Your Sewing Pattern Size

How do you work out which size sewing pattern to cut out?

If you’re making the Mathilde Blouse, the good news is that it’s loose-fitting, so relatively easy to get right. But whatever sewing pattern you're making, this post will outline how to choose the size that actually fits you, how to combine multiple sizes, and how to avoid patterns coming up larger than you expected.

Simplifying sewing pattern sizing

Our sewing patterns are labelled with numbers from 1 to 8, rather than the ready-to-wear sizing system (8, 10, 12 etc) which is often used on sewing patterns.

This is because the ready-to-wear sizing system can cause a lot of confusion and frustration, as the measurements vary between countries, between shops, and between sewing pattern companies. While it may be useful when you’re shopping for clothes, it doesn’t seem to make much sense when sewing our own clothes – when we should have more control over fitting to our unique shape, size and bust-waist-hip ratio. I’d encourage you to ignore “standard” sizes and instead look at the body measurements and the finished garment measurements listed on the pattern. This way we have more control over getting a better fit. Hooray!

1) Take your measurements

First things first - you need to know your vital statistics.

Measure yourself wearing your usual undies - or your bestest frillies if that’s what you plan to wear under the garment you’re making. Better still, get a special friend to take your measurements for you, to ensure the tape measure is level and to check you’re not lying about how big your boobs are (as if). There are lots of great tutorials around the internet about taking your body measurements – including this one.

For the Mathilde Blouse pattern, the main measurements you need are your:
- Bust - fullest part
- Hip - fullest part
- Waist – only necessary if it’s bigger than your bust or hip size.

2) Find your pattern size

Find your bust, waist and hip measurements on the Body Measurements chart in the instructions and circle them. If you're between sizes, opt for the larger one - you can always take it in when you try it on.

Does your bust-waist-hip ratio correspond more or less exactly to one of the sizes? Great! You’re pretty much done – find the corresponding lines on the pattern, which are marked with numbers and dashed style of line. If you like, you can draw over these lines in a coloured pen to make it easier to spot your size when you’re cutting out. You can stop reading here and start sewing – or if you’re interested in the fascinating topic of ease, read ‘Check the ease’ below before cutting.

Do your bust, waist and hip measurements span different sizes? That’s totally normal! Keep reading…

3) Combine multiple sizes

In the oldy woldy days, sewing patterns came in single sizes. Nowadays most patterns are printed with multiple sizes nested on the same page, meaning that you can easily draw between the lines to mix and match different bust, waist and hip sizes.

Let’s say your bust is 32in and your hips are 39in. On the Body Measurements chart, this makes your pattern Size 2 on the bust and Size 4 on the hips. The bust is often the most difficult part to alter on a pattern, so let’s choose Size 2 as our starting point.

On your pattern, use a coloured pen to draw a line connecting up the end points of the size lines – between Size 2 bust and Size 4 hips in our example. If the pattern line is straight, just use a long ruler; or if it’s curved, use a curved ruler or a gentle hand to fashion a similar line. If there’s a dart involved, close it up temporarily with tape or pins. This is your new cutting line. Do the same on both the front bodice and back bodice, or any other pieces that will be sewn along the line that you’re changing.

Optional: Check the ease

This bit is optional – you can trust the ease that’s been added to the pattern and get on with cutting out if you like. But if you often find yourself frustrated at patterns coming up much larger or smaller than you expected, it’s worth getting to grips with ease so you can adjust it to your own preference.

The garment measurements for your chosen size(s) will be bigger than your body, even on a close-fitting garment, to allow you to breathe and move around in it – this is the ease allowance. Different sewing pattern companies will add a different amount of ease depending on the target market they’re designed for and how comfy or sexy they want you to feel when wearing the garment.

You can work out the ease by subtracting the “Pattern Size - Body Measurements” from the “Finished Garment Measurements” listed on the pattern.

Now you know how much ease has been added, you can go for a slightly larger or smaller size depending on your preference. A loose-fitting garment, such as the Mathilde Blouse, will have a lot of ease as part of the design. If, on the other hand, you’re making a tighter-fitting garment, it’s up to you how tight is tight, but the amount of ease you may want to go for could be:

- Bust – 2 – 4in – you need the most ease here so your lungs can move in and out so you can breathe
- Waist – 1 – 2in – one inch of ease should do, but I must admit I sometimes add two so I have room for a big lunch!
- Hip – 2in – ease here will allow you to move about, sit down, bend or whatever else you get up to.

Optional: Other fitting adjustments

You should now have a pattern which fits your vitals. However, there are still loads of body measurements other than bust, waist and hip that we haven’t taken into account.

The Mathilde Blouse is relatively easy to fit, but some areas you may want to look out for are:

- Bust darts - Bust fitting can be a huge topic (see below), but as this blouse hangs loose, you may only need to shift the darts up or down a little so the dart points towards your nipple. (Yes, I said nipple.) Before you sew them in place, pin the darts on your fabric, try the garment on inside out, then move the dart position if necessary.

- Shoulders - If you have narrow or wide shoulders, you may want to take this part in or out – either on the pattern itself or just reposition the sleeves when it comes to sewing.

- Cuff band - Check this is at least an inch or two wider than the widest part of your forearm. The pattern piece is just a rectangle so it’s easy to lengthen it if you need to.

- Hemline - You may decide to lengthen or shorten the hem depending on your height and how you like to wear the blouse.

Fitting is a MASSIVE topic and I’ve only skimmed the surface here (hopefully enough for the Mathilde Blouse). I’ll outline the basic concepts of fitting in a future post, but if you have major fitting issues you may want to invest in a book such as Fit for Real People.

I hope this helps!


  1. Very helpful Tilly! I usually just drape muslin and go from there for all my dresses, but every once in a while I buy a pattern and go, "eek too many directions" - but I am going to tackle one! I will be coming back here for pointers :)


  2. I'm loving reading these posts, Tilly -- the layout and pictures are so crisp. Eye candy.

  3. Tilly, that's great. Brilliantly detailed. I wish I'd have had something so clearly explained when I first started!

  4. I'm always between different sizes. Next time I will know what to do, thanks!

  5. I'm loving your well explained instructions on how to tackle a pattern. I'm looking forward to buying some fabric and trying out your patterns :)

  6. Help me please?! So I am 5 bust and 3 hips so want to combine the sizes but do you just need to draw a line on the bodice pieces up the sides?. What about along the top of that piece? And if so how do you then join those lines?? And what size do I follow on the other pieces? Cuffs, sleeves etc. I'm so confused and have had to scrap first print out cos of all my crazy coloured lines. Dear god don't let me near fabric! This is my first attempt and have spent 24 hrs trying to work out what line I am following! I feel like such an eejit!

  7. Great post. I should've read up on sizing issues before cutting into fabric for my first skirt! Thankfully I erred on the side of caution in a massive way, so the skirt is saved, thanks to your post here. Very informative:)

  8. Such an informative post. I've learned a lot through your blog just today. I was wondering if you could advise on what I should do. My bust size is quite small but my waist can be a little bigger or little smaller than my bust size. Then my hips smaller than both. I feel like I'm completely disproportioned when it comes to patterns. Some patterns my bust and hip measurements aren't on there as they are too small and then my waist measurement can be anywhere between 8 and 12 (US I believe). How would I go about adjusting measurements to fit/ any advice would be great. Many thanks

  9. Hi, this isn't your fault but the link to 'Casey' for grading ("Casey can show you how") doesn't lead to anything. Do you know what happened to Casey?

  10. Hi Tilly, my 11 yr old daughter is larger than the "norm" 11yr and it is impossible to get clothes that are age appropriate and she finds shopping should destroying....she will not go into clothes shops now. So ok I am going to attempt to make your Agnes top. I am looking for advice on which size to go with ... her measurements are bust 35"/high waist - narrowest part 33"/ waist at belly button - widest part 36.5"/ hip -widest part 38". I was thinking of doing size 4 from shoulders to bust and trying to graduate out to a size 8??? As the side seam is a "S" shape where would I start to graduate from??

  11. I select the size I think is right, make it up in lining fabric, check fit, adjust accordingly before I cut the main fabric. Then the lining is ready to pop in when I'm done.


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