The importance of cohesive size charts
And how to get sizing right from the start...
I have recently started working with a successful brand who have been established for over 10 years within the motorcycle apparel market. They’ve worked closely with international factories and agencies over the years, but have never had in-house expert working with them on their clothing development. Because of this, they’ve been struggling with some areas of the development process and got in touch to see if I could help.
One of the biggest problems they’re facing is that their sizing is a little all over the place. For example, based on how it’s set up on each product, customers may be able to buy an XL tshirt, but may not be able to find a hoodie to fit as the current XL hoodie too small. However they do know that certain styles, their bread and butter options, sell really well with no comeback on sizing problems – a great sign.
The issue above on is not uncommon, how often do you buy different sizes in different stores… but to standardise across a wide range of products to a revamped size will take a lot of work behind the scenes and with the factory to correct.
The best way to avoid this headache, is to get your sizing right from day one.
This means putting thought into your size range, your customers realistic body shape / size, and getting your Tech Packs developed by a professional.
There are three main elements to cohesive sizing:
1. Body Reference Size Charts
2. Consistent grading across single / double sizing
3. Standardised Tech Packs
Body Reference Size Charts
Along with your garment size charts which give measurements for your physical designs, a second size chart should be included in every Tech pack for items worn on body. A “Body Reference Size Chart” tells you which size garment will fit your customers best based on their own body measurements. It also keeps brands accountable to make sure they are fitting samples on fit models with the right measurements.
I include a Body Reference Size Chart with every Tech Pack I create. Very often these measurements are:
- Bust or Chest
- Waist
- Hips
- Inside Leg
The Bust or Chest measurement should be measured, you guessed it, around your chest. General rule of thumb is to wrap a tape measure around your person, ensure it’s straight across your shoulder blades and across your nipples on the front! For women’s bras, underbust measurements should also be taken.
Waist measurements should be taken around the natural waistline at belly button height. This is usually around the smallest circumference on women, but does slightly vary. The biggest cause of confusion for this measurement is that most tailored mens trousers are sized by Waist Size, a 32” waist for example. However this measurement is not taken around a man’s midriff, unless this is where you wear your trousers! My background in active & leisure wear means I don’t come across this issue very often, as more relaxed garments are often sized by Small – Medium – Large etc, instead of by waist size. For the purpose of your “Body Reference Size Charts” you should give Waist measurements as taken at belly button height. If your brand has men’s trousers sized by Waist Size (32” etc) then a separate size guide just showing these measurements in inches along with leg length will suffice.
Hips measurements are to be taken around the fullest part of the bottom around the hips – yes even if you have a big bum as I do! Reason being, the Hip measurements taken from your body, must align with hip measurements on your garment. In other words, you have to make sure there is enough material to go around the widest part of your hips / bottom!
Inside Leg should be measured from the top of our inside leg (make sure to measure high enough for correct dimensions!) right down to the bottom of your ankle. As standard – garments often don’t grade or have little difference between inseam length between sizes. The exception to this is if a brand decides to offer a range of leg lengths, short, regular and long for example.
But how do you build a full Body Reference Size Chart?
The easiest way to produce a Body Reference Size Chart is to find an existing brand who’s garments you know fit well across sizes, and start there. Review the differences between sizes, compare it to your chosen size range and sizing set up. Just be sure to check whether they are using Single or Double sizing (more on this below!).
Once you’ve got your chart set up, you must then make sure that you are fitting samples on someone who aligns to this chart! By this I mean, if you are ordering size Medium samples thinking you would normally order a Medium so will fit them yourself, this is absolutely fine, but please check that your body measurements align to the size Medium you’ve now set up in your Body Reference Chart. The idea is to ensure that this sample size fits you perfectly, so although this sounds obvious, there’s no point fitting a sample on you if you do not fit in with your size chart.
From a personal perspective, I know I have long arms and short body, so if I ever fit anything on myself I have to take this into consideration. If a long sleeved tshirt looks like it could do with an extra cm or two on me, the chances are, for the majority of people with normal length arms, these extra cm’s are unnecessary so I wouldn’t make this change.
So to summarise…
Step 1 – Establish a Body Reference Chart based on the size range you want to offer.
Step 2 – Take your own measurements (or the measurements of your fit model) and make a note of what size samples will need to be ordered. Double check these measurements align to your Body Reference Chart!
Consistent grading across single / double sizing
Grading is the term for the difference in dimensions between your sizing. Good grading is crucial for good fitting garments, and although there are some industry standards every garment should be reviewed at Tech Pack stage to make sure nothing in the design requires a grading update.
Grading is set per measurement point in your Garment Size Chart, and by your Size Range, so whether your garment is being sold in Single or Double Sizing.
Single Sizing =
Often used for tailored garments without stretch, or with brands who can afford to order a wider range of sizes.
Mens: chest or waist size (32”, 34”, 36” etc)
Womens: size 10, 12, 14 etc
Double Sizing =
Has a larger gap between sizes, where fit isn’t as crucial or stretch fabric is involved. Usually labelled as Small, Medium, Large etc. It’s common to find sizing described as something like Small = 8 -10, Medium = 10 – 12, Large = 12-14 for example.
*WARNING*
The way a size is labelled can be misleading. For example, a tshirt could be set up in Single Sizing with smaller increments between each size, but still labelled as XS, S, M, L, XL, XXL etc… The only way to check is to look at the size charts!
As a brand, you can call your sizes whatever you’d like, just make sure Body Reference Size Charts are easily available for your customer. It’s also important that for new styles, you order a full size set (one sample of every size) at least once to fit and review.
One more crucial thing about Grading – is not to mess with it across styles. Your garments should all grade the same at each measurement point regardless of the item if they have the same size range. This is to avoid the issue my current client is having where different garments all fit differently. By having their t-shirts grading by one amount, and the hoodies grading by a smaller amount they will run out of sizes before achieving the same dimensions. Visual guide below:
So, in the example above, the medium size will fit the same person fine. However if you wear an XL, either the t-shirt is going to much larger on you than expected, or the Hoodie will come up far too small. Likewise, if you need an XS tshirt, you just don’t have an option for a Hoodie that is small enough.
There are pros and cons to double or single sizing – you can cover a wider customer base on Double Sizing by ordering less stock, whilst more accurate fits are possible on Single Sizing. It’s also totally okay to offer both types of sizing across different garments. You may want to offer a double sized hoodie which has a more relaxed fit, and then single sized trousers which are more tailored. Just remember to provide clear Body Measurement Charts for each product and ensure garments are labelled appropriately keeping the Small – Medium – Large options for Double Sized Garments only.
Step 3 – Decide on the sizing options for your brand (single or double) with any exceptions planned for.
Standardised Tech Packs
Taking all of the information you’ve gathered above, it’s time to get Tech Packs and therefore Size Charts made.
Every style should have a Tech Pack made with both the relevant Body Reference Size Chart & Garment Size Chart included. Through sampling & fit sessions, these size charts will be tweaked and approved, and you will slowly build up a reference of garments for your brand. For example, once you have a Hoodie Size Chart approved you can reuse this time and time again needing only to update measurements relevant to the new design, for example pocket position, artwork designs etc.
I strongly recommend hiring a professional to create size charts. This is so they can use their experience and knowledge on grading and garments to fast-track your pattern cutting & sampling process. If you send out a Garment Size Chart that isn’t quite right, I guarantee you will get samples that aren’t quite right too. Factories aren’t in the business of updating size charts to fit, they will just make samples with the information provided to them.
Working with a freelancer Garment Tech means they can also help you with fit sessions and sending clear, accurate fit comments to suppliers, again for efficient sampling!
Step 4 – Have Size Charts made with Grading to match your chosen sizing. Do not mess with these grading points unless recommended by a professional!
Step 5 – Sample, fit & perfect your range with the help of a professional.
Hey, I’m Demi 👋
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