Tech Pack vs Spec Sheet: What’s the Difference?

What Exactly is a Tech Pack?

Fashion. The word conjures up images of designers with big personalities, shows like Project Runway, gorgeous fabrics, and mood boards: all the things that are aesthetically pleasing and attractive to the eye. No one thinks of the hard, boring work that goes into the finished garments, and all the jobs that exist in fashion that are not so glamorous. One of those roles is that of the Technical Designer.

I have been working as a Technical Designer for over half a decade and find that one of the most confusing things for new designers to understand is what tech packs are, how they vary from spec sheets, and what the job of each of these documents are. Well, I am here to help unravel these mysteries!

A specification sheet is a page within the technical package. The technical package is a document that tells the manufacturer every detail of your product, how it is to be made, and in what order. It is insurance that your manufacturer is fully aware of how to make your product and allows you to chargeback mistakes to the manufacturer, should they not follow your instructions.

Let’s Talk More About Tech Packs

Each tech pack –as it is colloquially called– will be specific to your product. Some will need more pages, some less. It is a living document that is altered frequently while your product is developed and sampled. 

Larger companies use software that tracks all changes to the product with dates. This software can also create reports based on these changes. If you are like most small, independent designers, you are going to have to manage with a combination of Excel or Google Sheets and project management tools like Trello or Asana. These tools are very flexible, quick to learn, and either free or inexpensive to purchase.

Using a template to create your first tech pack is a wise decision, as it allows you to see what is needed, in a general sense, to produce your product. We have one here. 

What Tech Packs Typically Include

• Technical sketches, with callouts
• Inspiration Images/Fashion Drawings/Retail Sample Images
• Color up drawings
• Bill of Materials
• Order of Construction
• POM (Points of Measure, also known as a Spec Sheet)
• Sample Review with images and corrections notated:

P1 (Prototype 1)

P2/P3

JSS (Jump Size Samples)

PP (Pre-Production) Samples

Salesmen Samples

TOP (Top of Production) Samples

• Grade Rules (often combined with POMs)
• Special Details
• Hang Tags/Labels Artwork
• Finishing and Packaging Artwork and Callouts

Not all tech packs will include all of these things, and some will also require more details. Adjust to your product’s needs. Next, we are going to focus on the Specification Sheet, as this is critical in developing your product, and keeping it consistent over time.

What is a Spec Sheet

Point of Measure –or POMs, as I will refer to them– is a list of the specific locations for measurements of the finished garment dimensions, each point labeled with a reference number, i.e. 001, 002, 090, etc. (See image below)

POM #	Description:	BASE SIZE
001	CF Length from HPS to Hem	30.25″
003	Neck Opening Width, from HPS-HPS	10″
004	Front Neck Drop, from HPS	10″
011	CB Length from HPS to Hem	31.35″
032	Sleeve length from CB Neck to Sleeve Hem, 2 point measure	35″

These reference numbers will link back to a document you need to provide your QC team and your Technical Designer (or yourself) called a Points of Measure Handbook.

This handbook shows visually exactly where on the garment a measurement is to be taken and has a reference number attached to it. Over time, you will memorize the reference numbers and it will be very easy for you to quickly check your measurements.

Why are POMs Important?

These measurements ensure your product not only fits as intended, but also allows you to see the amount of variance that is happening once a garment is cut and sewn. If the garments measure far outside what is an acceptable amount of tolerance, you can tell your manufacturer to pay for the mistakes they made. It is insurance that you are getting what you paid for. I prefer to keep my tolerances very tight: 1/8” – ¼” for widths, ½” for lengths.

Many fast fashion and knitwear companies have larger tolerances, which allow them to have a broader range of “fit” within a single size. This is because speed and efficiency are worth more than the quality of fit in their business. If your company values fit more than speed, setting tolerances lower is a good choice. Both are perfectly valid options, you just need to be aware that higher tolerances allow for more variance within a single size.

Tolerate What?!

What about those tolerances? How do those work?

POM #	Description:	TOL +/-	SM	MED	LRG	XL
001	CF Length from HPS to Hem	1/2″	29	30	31	32

Notice in the tolerance label at the top of the column there is this weird formula: +/-. What does that mean?! This notation indicates that the POM can be larger or smaller than the spec by the notated measurement. 

Example: POM 001 is listed at a tolerance of +/- 1/2”. The spec measurement for the base size is 30”. The physical garment sample is measuring at 31”. This means that the POM is OVER spec by 1”, which is +3/4” tolerance.

This is also very important information to give your factory. Somewhere between the cutting, sewing, and finishing, there was a problem that ended up making your garment out of spec. Perhaps they cut the wrong size and mislabeled it.

Or perhaps the sewist used too narrow of a hem, or perhaps the marker they are cutting from has an old pattern on it. This gives the factory clues of what to look for, find the miscommunication, and also correct the mistake.

Let’s Talk Layout 

I have inserted a spec sheet below to use for our example. This is a real product I designed and developed for a client. As you can see, there are a lot of POMs. 

For your initial sample, you want to fill out the base size column ONLY. This is the size you are going to grade your garment up and down from. It is best to use a size in the middle of your size range as your base size, as this allows the shape of the garment to translate more easily to the other sizes. Provide this sheet to the person creating your grading, along with your grade rules.

NOTE: This example does not follow that rule, as the client used themselves as a fit model. In addition, this spec doesn’t include the tolerance column, as that had not been determined at the time of creation. 

Growing and Shrinking: Basic Grading

Grade Rule: a formula used to create new sizes using measurements of the base size.

An example of a grade rule for a five size pattern set would be: 2”>2”>2”>2.5”>2.5”

This means that the garment gets bigger in circumference by 2” each size from an XS to Medium, and 2.5” between the Medium to Large, and Large to XL. This also tells your patternmaker the fractions of an inch that they need to move points on the pattern to make your garments grow and shrink for each size.

I will go into grading more in-depth in future posts, but for now, you just need to know how much bigger around each size should be, and how much longer each size should be. 

A great way of figuring out what your grade rules should be is to look at the size charts of your top 5 competitors (available on their websites) and notate the difference in measurements between the bust, waist, and hip circumferences, between sizes.  

Example of Grading

This example is for Melissa McCarthy Seven7. To determine the difference between size 0X and the 1X bust measurement, subtract the 1X highest measurement from the 0X highest measurement, or: 46.5”- 42.5”= 4”. This is a 4” grade rule.

(see yellow highlighter)

 

Research Chart for Sizing	Letter/ Number Size	Bust	Waist	Hips
Melissa McCarthy Seven7	0X/10W-12W	39-42.5	32.5-36	42.5-46
	1X/16W-18W	43-46.5	36.5-40	46.5-50
	2X/20W-22W	47-50.5	40.5-44	50.5-54
	3X/24W-26W	51-54.5	44.5-48	54.5-58
	4X/28W	55-58.5	48.5-52	58.5-62
	GRADE RULE	4”, 4”, 4”, 4”

 

Below is a comparison chart I created for my company, Belle Ampleur when trying to decide on my grade rules and sizing chart. This chart shows the size 16 (base size) for each competitor’s brand, with their measurements for the bust, waist, and hips. The grade rule is based on the entire size spread for that brand. 

 

Size 16 Base Size for Brands	Letter/ Number Size	Bust	Waist	Hips	Grade Rule, Bust Circ, based on size chart online
Melissa McCarthy Seven7	1X/16W-18W	43-46.5	36.5-40	46.5-50	4″
Alice & You	16	46.75	39.25	48.75	2,3,3,3,2,3,2,3,2,3,2
Adrianna Papell	1X/14W-16W	43-44.5	37-38.5	47.5-49	4″
Alfani Women	16	45.5	38.5	48.5	2,3,2.5,2.5,2.5,2.5
City Chic	S/16	45.2	38.2	50	2,2,3,3,3
Eloquii	16	44	37	47	2,2,2,2,2,3,3
Eshakti	16W	46.5	39.5	49.5	2,2,2
Igigi	16	46.5-48	40.5-42	50.5-52	2,2,2,2,2,2,3,3,3
Torrid	1/14-16	42-46	36-40	46-50	2,2,4,4,6,4,6
Average Dimensions	16	45.66	38.91	48.88
Belle Ampleur Standard	16	46	39	49
Purple indicates Key Retailers for comparison

 

Now What?

Once final changes have been made to your base pattern, THEN you can work with your patternmaker to fill out the POMs on the spec sheet for the other sizes. I like to input the information as formulas into the cells, so if, in the future, you want to change the measurements of the base size, the other columns will automatically update.

 

A	B	C	D	E	F	G
1	POM #	Description:	XL	2XL	3XL	4XL
2	001	CF Length from HPS to Hem	57	58	59	60

Example: CF Length measurement for a size 2XL is 58”. Each size gets smaller or larger by 1”, so my formula for backward change would be sum=(E2-1), and my formula for forward change would be sum=(E2+1), sum=(E2+2), etc. 

This is very helpful for future new style development. Base a new style on an old spec, and fiddle with the base size measurements to get the garment you want! 

HALP! So Confused!

Don’t worry if you are super confused! You can ask your patternmaker to do all of this for you but having a general idea of how this works is very important, so you can communicate your needs and changes with authority, and you can catch mistakes early before items have been cut for production.

Whew…That Was A LOT.

Technical design is a lot of math, patience, tracking changes, and ensuring people are following all directions exactly. Tech packs are your lifeline in the ocean of details. Keep it organized, updated, and put the date on every single change you make. You won’t be able to remember everything, so write it in your tech pack! Your spec sheet is the blueprint for your garment: use it to double-check your finished garments.

 If you are feeling overwhelmed, or are afraid of making mistakes, you are not alone! Ask your patternmaker to double-check your spec sheet. Ask your factory to double-check it against the marker they are using to cut your sizes. CHECK EVERYTHING and double-check it. Mistakes will happen. That is inevitable. The goal is to minimize them, and that means being organized and knowing your product inside and out.

Final Thoughts

Remember: a spec sheet is a list of POMs that define the size of your finished garment. A spec sheet is one of many pages within your tech packs. A technical package is the instructions to your factory on how to make your product.

Easy, right?