This page explains how to read a woven fabric's construction spec: ends per inch (EPI), picks per inch (PPI) and fabric width. It is for anyone who reads or writes a fabric spec at work: a merchandiser, a buyer, a mill sales desk, or a student. This lesson mainly teaches an information flow: three figures arrive together on a spec sheet or in a reorder note, in a fixed order, and the reader must know which figure is which before quoting, confirming or producing anything. A mill sales desk, a buyer confirming a reorder, and a merchandiser checking a spec line all meet the same three-figure format.
Without this skill, a person reads a line such as "108 x 58, 58 inch width" and cannot say with confidence which number is the warp count, which is the weft count, and which is the separate width figure. Confirming the wrong density back to a customer, or reversing which number is which, is not a small slip: EPI and PPI describe two different directions of yarn, and width is a third, separate fact again. A mill that misreads its own construction line risks producing a fabric the customer never actually asked for.
You need: lesson 3.1, for warp and weft yarn crossing on a loom, and lesson 3.2, for the idea that a woven fabric has a named structure. Neither is required here, but both make the reasoning behind EPI and PPI clearer.
By the end of this lesson you can:
Not covered here: how EPI and PPI are set on a loom (a later lesson), fabric-consumption calculations using width (course 3.3), and GSM to ounce conversion (also course 3.3).
| Term | Meaning |
|---|---|
| Ends per inch (EPI) | The number of warp yarns packed into one inch of a woven fabric's width. |
| Picks per inch (PPI) | The number of weft yarns packed into one inch of a woven fabric's length. |
| Fabric width | How wide a fabric comes off the loom, usually stated in inches or centimetres, separate from EPI and PPI. |
| Warp and weft | The two sets of yarn crossed on a loom to make woven fabric: warp runs the length, weft runs across it. |
| Construction line | The short, standard way a spec sheet or reorder note states a woven fabric's EPI, PPI and width together. |
| Greige fabric | Fabric, knitted or woven, that has not yet been dyed or finished. |
Ends per inch (EPI) counts the number of warp yarns packed into one inch of fabric width. Picks per inch (PPI) counts the number of weft yarns packed into one inch of fabric length. Together, EPI and PPI describe how densely a woven fabric is constructed, the woven equivalent of a knit fabric's gauge: a higher EPI or PPI generally means a firmer, more tightly woven fabric. Fabric width, usually stated in centimetres or inches, is the third figure a construction spec states, describing how wide the fabric comes off the loom. These are standard textile-measurement definitions, not a claim about any one fabric's own fixed numbers: this academy's cast has no fixed EPI/PPI figure for Order A's T-shirt or Order B's denim, so this lesson teaches how to read a construction line on a real spec sheet, not a specific number to memorise.
| What can differ | The shapes you will meet | Why it matters |
|---|---|---|
| Ends per inch (EPI) | Warp yarn density; read as the first number in a construction line; a higher EPI generally means a firmer, more tightly woven fabric. | Nile Spinning's counterpart on the weaving side, Suez Denim, must confirm this figure before agreeing to weave a fabric to spec. |
| Picks per inch (PPI) | Weft yarn density; read as the second number, after EPI, never alone, since a fabric's overall density depends on both figures together. | A mill or buyer who reads only PPI, or only EPI, has not read the fabric's actual density. |
| Fabric width | The third figure, usually stated separately from EPI/PPI (for example "58 inch width" or "150 cm"), needed later to calculate how much fabric a pattern piece will use (course 3.3). | Confirming the wrong width can mean a fabric that does not match a pattern's cutting requirements downstream. |
| A typical construction line format | Spec sheets and reorder notes often write these three figures together, for example "108 x 58, 58 inch width" (108 EPI, 58 PPI, 58-inch width): a real industry format, not a claim about any one order's own specific numbers. | Recognising the format lets a reader separate the three figures correctly even when a note is brief. |
| Woven fabric families beyond denim | Shirting, chino and home-textile wovens all state a construction line in the same EPI/PPI/width format, whatever the end product. | The reading skill this lesson teaches is not specific to denim; it applies to any woven construction spec. |
Neither EPI nor PPI describes a fabric's density on its own: a mill, buyer or merchandiser reads both figures together, then reads width as a separate, third fact.
The case we followSuez Denim, the denim mill in this academy's cast, normally weaves Order B's own export denim for Delta Garments. This lesson follows a different, domestic scenario at the same mill: Suez Denim's domestic sales desk receives a construction request for a Make to Stock reorder from a domestic customer restocking its own shelves, not an export order placed against a confirmed buyer contract. Before Suez Denim can quote a price, its sales desk must confirm it has read the customer's three-figure construction line correctly: EPI, then PPI, then the separately stated width.
This domestic, Make to Stock reorder is a distinct case from Order B's own fixed export denim order: it uses the same mill and the same reading skill, but a different customer relationship and a different business reason for the order.
The worked numberNo new figure is invented for this academy's cast. To practise the reading skill, this lesson uses a generic, clearly-labelled sample construction line, illustrative of the industry format only, not a fact about Order A's T-shirt or Order B's denim (neither has a fixed EPI/PPI figure in the master cast, per docs/02 section 18):
The same three-part read applies to any construction line, whatever the actual numbers a real spec sheet states.
| Position in the line | Figure | What it measures |
|---|---|---|
| First number | 96 (illustrative) | Ends per inch (EPI): warp density |
| Second number | 60 (illustrative) | Picks per inch (PPI): weft density |
| Separate width figure | 60 inch (illustrative) | Fabric width |
A common mistake is reading "96 x 60" as if it were itself a width measurement, similar to how a room's dimensions might be written, rather than as two separate density figures. A second version of the same mistake is reversing which number is EPI and which is PPI. Both mistakes cost a mill or factory the same way: a construction line's two density figures and its separate width figure describe three different facts about the fabric, and EPI and PPI are read in a fixed order, warp first, weft second, by industry convention. A mill or factory that misreads a construction line could quote or produce a fabric with the wrong density entirely, discovered only once the fabric is already woven and compared against what the customer actually asked for.
A woven fabric spec states three separate facts. Two of them describe how tightly the fabric is woven: how many lengthwise yarns sit in one inch of the fabric's width, and how many crosswise yarns sit in one inch of its length. The third fact, stated on its own, says how wide the fabric actually is. These three figures are usually written together in a short line, always in the same order: the lengthwise count first, the crosswise count second, then the width, separately. Reading them out of order, or mixing the width in with the other two, means telling a customer or a factory the wrong thing about the fabric, a mistake that is only caught once the fabric already exists.
Suez Denim's domestic sales desk, handling a Make to Stock reorder for an existing domestic customer:
The document the sales desk reads, the reorder note exactly as quoted:
What are the three figures this note states, and in what order? Decide before you open the answer.
The note states 108 ends per inch (warp density), 58 picks per inch (weft density), and a 58-inch fabric width, in that order.
The two facts that decide this are the fixed reading convention, EPI first, then PPI, then width stated separately, and the note's own three numbers, read in the order they appear: 108, then 58, then "58 inch". Because the format always runs EPI, PPI, width, the 108 is never mistaken for anything but the warp density, and the 58 that appears twice, once as PPI and once inside the width figure, is kept straight only by reading the note in its fixed order rather than picking numbers out of it.
Had the sales desk instead read "108 x 58" as a single width measurement, or swapped which of the two numbers was EPI and which was PPI, it would have confirmed the wrong density, the wrong width, or both back to the customer, a mistake discovered only once the wrong fabric had already been woven.
This risk is framed qualitatively, because no specific order in this academy's cast has an EPI or PPI figure fixed against it. Misreading a construction line, for example confirming the wrong fabric width, or reversing EPI and PPI, risks producing a fabric that does not match a pattern's cutting requirements downstream, or a fabric that is simply not what the customer asked for. This mismatch is discovered only once the fabric has already been woven, by which point the yarn, the loom time and the sales desk's own confirmation have all already been spent. Reading a construction line in its fixed order, EPI, then PPI, then width, is a small step designed to prevent exactly this kind of late, costly mismatch.
This course's woven construction reference sheet lists the three basic weave structures and their typical use. This lesson's reading skill feeds the sheet's own notes column: once a learner can read a construction line correctly, they can record whether a given weave and construction fits a new product brief.
| Question | Illustrative example (filled in) | Your construction line |
|---|---|---|
| First number: EPI | 96 | |
| Second number: PPI | 60 | |
| Separate width figure | 60 inch |
Download the woven construction reference sheet linked from this course, and use its notes column to record how a real construction line you meet at work reads against this three-part method.
1. What does "ends per inch" (EPI) measure?
2. In a construction line written as "108 x 58", which number is PPI?
3. A different mill's spec sheet states a construction line as "84 x 64, 44 inch width". What is this fabric's fabric width?
| EN | AR | FR | TR | Meaning |
|---|---|---|---|---|
| Ends per inch (EPI) | عدد خيوط السدى في البوصة (EPI) | Fils de chaîne au pouce (EPI) | İnç başına çözgü sayısı (EPI) | The number of warp yarns packed into one inch of a woven fabric's width. |
| Picks per inch (PPI) | عدد خيوط اللحمة في البوصة (PPI) | Duites de trame au pouce (PPI) | İnç başına atkı sayısı (PPI) | The number of weft yarns packed into one inch of a woven fabric's length. |
| Fabric width | عرض القماش | Laize (largeur du tissu) | Kumaş eni | How wide a fabric comes off the loom, usually stated in inches or centimetres, separate from EPI and PPI. |
| Warp and weft | خيوط السدى واللحمة | Chaîne et trame | Çözgü ve atkı | The two sets of yarn crossed on a loom to make woven fabric: warp runs the length, weft runs across it. |
| Construction line | سطر تركيب النسيج | Ligne de construction (armure) | Yapı (konstrüksiyon) satırı | The short, standard way a spec sheet or reorder note states a woven fabric's EPI, PPI and width together. |
| Greige fabric | قماش خام (جريج) | Tissu écru (grège) | Ham (gri) kumaş | Fabric, knitted or woven, that has not yet been dyed or finished. |
You now know how to read the three figures on a woven construction line. The next lesson looks at warp and weft themselves: which yarn runs the length of the fabric, which runs across it, and why a mill treats them differently before a single pick is woven. Back to the course map