How to Read a Fabric Spec Sheet: Yarn Count & Construction Explained

If you're not sure what half of that means, you're not alone. Most buyers — even experienced ones — don't fully understand every number on a fabric spec sheet. They know enough to place an order, but not enough to compare two fabrics with confidence or spot a bad spec before it turns into a bad shipment.

This guide breaks it all down in plain language — no textile engineering degree required. By the end, you'll be able to pick up any shirting fabric spec sheet and know exactly what you're looking at.

The Two Numbers That Define a Fabric

Every woven shirting fabric is defined by two core specs:

1. Yarn count — how fine or coarse the yarn is
2. Construction — how tightly those yarns are packed into the fabric

Everything else — the weight, the feel, the drape, the price — flows from these two numbers. Get them right, and you're sourcing with precision. Ignore them, and you're guessing.

Yarn Count: The Fineness of the Thread

Yarn count tells you how thick or thin the yarn is — the individual thread, before it's woven into fabric.

In shirting, it's almost always written as a number followed by "s" — like 40s, 60s, 80s, or 100s. You might also see it written as Ne (which stands for English cotton count), but it means the same thing.

How it works

Here's the simple way to think about it: the number tells you how fine the yarn is.

• 40s = relatively thick yarn
• 80s = much finer yarn
• 100s = very fine yarn

The higher the number, the finer the yarn.

Imagine stretching out one pound of cotton into yarn. With thick yarn (40s), you get fewer, shorter lengths. With fine yarn (100s), you can stretch that same pound into many more lengths — because each thread is thinner.

Why does this matter? Finer yarns produce smoother, lighter, more luxurious-feeling fabric. But they're also more delicate and more expensive to produce. So the yarn count is essentially telling you where a fabric sits on the scale from "basic" to "luxury".

What the prefixes mean

On a spec sheet, you'll often see letters before the count number. These tell you how the yarn was spun:

So when a spec sheet says CPT70, it means: compact-spun, 70s count yarn. In plain terms — this is a high-quality yarn that's fine, smooth, and produces a clean-looking fabric.

If you see just a number with no prefix (like 70s), it usually means combed ring-spun — which is standard good quality. The prefix is there to tell you something extra about how it was made.

The yarn count range for shirting

For most shirt brands, the sweet spot is 60s to 80s. That's where you get genuinely good quality without sacrificing durability. Go below 50s and the fabric starts to feel rough. Go above 100s and it becomes delicate — great for luxury, impractical for everyday wear.

What about warp × weft?

When a spec sheet shows yarn count as CPT70×CPT70, the two numbers represent:

• First number = warp yarn (the vertical threads that run up and down the fabric)
• Second number = weft yarn (the horizontal threads that run side to side)

If both numbers are the same (like 70×70), it means the same yarn is used in both directions. If they're different (like 80×60), the vertical threads are finer than the horizontal ones — which can affect how the fabric drapes and feels.

Most shirting fabrics use the same count for both, so you'll often see it written as just CPT70 instead of CPT70×CPT70 — they mean the same thing.

Construction: How Tightly It's Woven

The second critical number on a spec sheet looks like this: 200×100 or 133×72 or 110×90.

This is the fabric construction — also called thread density. It tells you how many threads are packed into one square inch of fabric.

• First number = how many vertical threads per inch (called "ends per inch" or EPI)
• Second number = how many horizontal threads per inch (called "picks per inch" or PPI)

You don't need to remember the technical terms. Just know: first number = vertical, second number = horizontal.

What it means in practice

Picture one square inch of fabric — roughly the size of a postage stamp.

200×100 means there are 200 vertical threads and 100 horizontal threads crammed into that tiny square. That's 300 threads total — an extremely tight, dense fabric.

110×70 means 110 vertical and 70 horizontal — only 180 threads total. That's a more open, breathable fabric with more space between the threads.

Why does construction matter?

Higher construction numbers generally mean:

• Tighter weave — less air between yarns
• Better durability — more resistance to tearing and pilling
• Smoother surface — less texture, more refined appearance
• Higher weight — more yarn = more grams per metre
• Less breathability — tighter = less airflow

Lower construction numbers mean:

• Softer, more breathable fabric
• Better drape — the fabric moves more freely
• Slightly less durable — fewer threads holding it together

Common construction ranges for shirting

The relationship between yarn count and construction

Here's the key insight most people miss: finer yarn allows tighter construction.

Think about it this way — if you have thick rope, you can only fit a few pieces side by side in a small space. But if you have thin thread, you can pack hundreds into the same space. It's the same principle with fabric.

You physically can't fit 200 threads per inch using 40s yarn — the threads are too thick. But with 70s or 80s yarn, you can. That's why premium fabrics usually have both a high yarn count AND high construction — the two go hand in hand.

So when you see CPT70×CPT70 / 200×100, it's telling you: fine compact-spun yarn, woven extremely tightly. That combination is what produces a smooth, crisp, high-end shirting fabric.

The Other Specs on the Sheet

Yarn count and construction are the core specs, but you'll see other information too. Here's what the rest means:

Composition

100% COTTON — straightforward. You'll also see blends like 60% Cotton 40% Polyester (CVC) or 70% Cotton 30% Linen. The composition tells you the fibre content, but not how it's spun or woven — that's what yarn count and construction do.

Width

57/58″ is standard shirting fabric width (around 147cm). Some fabrics come at 44/45″ (narrow) or 60/62″ (wide). Width matters for cutting efficiency — wider fabric means less waste per shirt and lower cost per unit.

Finish

LIQUID AMMONIA — this is a premium finishing treatment where the cotton fabric is briefly exposed to liquid ammonia under controlled conditions. This permanently changes the internal structure of the cotton fibres — think of it like straightening out the fibres at a molecular level. The result:

• Noticeably softer hand feel
• Improved wrinkle recovery
• Better dimensional stability (the fabric holds its shape and shrinks less after washing)
• Smoother surface with a slight natural lustre

Other common finishes you'll see:

Weight (GSM)

Some spec sheets include GSM (grams per square metre). This tells you how heavy the fabric is:

• 80–100 GSM: Very light — summer shirting, potentially sheer
• 100–130 GSM: Standard shirting weight
• 130–160 GSM: Medium — oxford cloth, autumn shirts
• 160+ GSM: Heavy — more structured, jacket-weight

GSM is the result of yarn count + construction + weave. Two fabrics can have the same GSM but feel completely different because of how they're woven.

Putting It All Together: Reading a Real Spec

Let's go back to the original example:

Bottom line: This is a premium shirting fabric. Fine compact yarn, tightly woven, with a luxury finish. The kind of fabric you'd use for high-end dress shirts or premium retail collections.

Three Mistakes Buyers Make with Specs

Want to See the Difference Yourself?

Numbers on a spec sheet tell part of the story. The rest comes from touching the actual fabric — feeling the difference between 40s and 80s, between a standard finish and liquid ammonia, between a loose weave and a tight one.

We can send swatch cards across the range so you can compare side by side. Complimentary swatch cards for qualified trade enquiries.