A knot is the unit a hand knotted rug is made of. The weaver ties a short length of yarn around the warp threads, row after row, and the cut ends of those knots become the pile you walk on. Count how many of them fit into a square inch and you have KPSI, knots per square inch, the number the rug trade quotes more often than any other and misuses more often than any other.
This guide covers the two knots that account for nearly every antique rug in existence, how to count knot density yourself, and the part almost nobody says out loud: knot count is a description of a rug’s resolution, not a score of its quality. It is the companion piece to our guide on rug foundations, warps and wefts, which covers the grid the knots are tied onto, and to the five minute identification checklist.
What is a rug knot?
On a hand knotted rug, the weaver wraps a piece of dyed yarn around a pair of adjacent warp threads, pulls it tight, and cuts the ends off short. That single wrap is a knot. A row of them is completed across the width of the rug, one or more wefts are passed to lock the row down, and the weaver starts the next row on top of it. A room size carpet is a million or more of these tied by hand, one at a time.
Two consequences follow immediately, and both are useful to a buyer. First, the design exists only as knots, so on a genuine hand knotted rug the pattern is fully visible on the reverse as individual coloured nodes, with nothing printed, glued or backed over it. Second, the knots are not attached to the foundation so much as gripped around it, which is why pile can wear down to nothing and the rug still holds together. The structural work is done by the warps and wefts underneath.
Not every rug has knots at all. A kilim is built entirely from wefts and has none, which our antique kilim guide covers, and an American hooked rug is loops pulled through a backing, also with none. Both are worth knowing about precisely because they make it obvious what a knot is by showing you a rug without any.
What is the difference between the symmetric and asymmetric knot?
There are two, and the difference is simply how the yarn is wrapped around the pair of warps.
The symmetric knot, also called the Turkish or Ghiordes knot, loops around both warps and brings both ends up together between them. It sits square on the foundation, grips hard, and produces a sturdy, slightly blockier pile. It is the knot of Anatolian weaving, of the Caucasus, and of Kurdish and northwest Persian work.
The asymmetric knot, also called the Persian or Senneh knot, wraps fully around one warp and only passes behind the other, so one end comes up between the pair and the other comes up outside it. Because it is not locked symmetrically, it can be packed more tightly and can curve around a drawn line more smoothly. It is the knot of the Persian city workshops, of India, of China, and of Turkmen weaving.
Be careful with the names. They are labels of convenience assigned by nineteenth century European writers, not reliable statements of origin. The “Turkish” knot appears throughout Persia, the “Persian” knot appears in Turkey, India and China, and the town of Senneh that gave the asymmetric knot its second name is a case scholars still argue over. Use the knot to help place a rug, never to decide it on its own.
| Symmetric (Turkish, Ghiordes) | Asymmetric (Persian, Senneh) | |
|---|---|---|
| How it is tied | Around both warps, both ends up between them | Around one warp, one end up between the pair |
| Where it dominates | Anatolia, the Caucasus, Kurdish and NW Persian weaving | Persian city workshops, India, China, Turkmen |
| Practical effect | Robust, grips well, favours bold geometry | Packs tighter, follows a curve, favours fine floral drawing |
| Example in our collection | 1900s Caucasian Kazak | Antique Persian Kashan |
The design consequence is real and it runs one way. Tight curvilinear floral drawing, the kind that fills a Kashan or a Kerman, needs the asymmetric knot and a fine foundation to render its curves without them turning into staircases. Bold geometry does not need either, which is why Caucasian and Anatolian weavers had no reason to abandon a knot that held better.
How do you count KPSI on a rug?
Turn the rug over and work on the back, where each knot shows as a small node. Then:
- Lay a ruler flat and count the nodes across one horizontal inch. That is the knot count per inch horizontally.
- Count the rows of nodes down one vertical inch. That is the count vertically.
- Multiply the two. Ten across by twelve down is 120 KPSI.
Two cautions. Measure in the field, away from the border and away from any repair, because density varies across a rug and a rewoven patch is not the weaver’s work. And take more than one reading on a hand woven object; a weaver’s tension changed with the season, the light and the year, and antique rugs are routinely five or ten percent denser at one end than the other. That drift is a sign of hand weaving, not a defect.
You may also see density quoted as knots per square decimetre, common in European and auction catalogues. Divide by roughly 15.5 to convert to KPSI.
Does a higher knot count mean a better rug?
No, and this is the most expensive misunderstanding in the trade.
Knot density describes how finely a design can be drawn. It is closer to the pixel count of a photograph than to a grade. A high count lets a weaver render a curved vine or a face; it says nothing about whether the wool is good, whether the dyes were natural, whether the drawing has any life in it, or whether anyone wants the rug in their house.
Our own inventory says so plainly. Across the antique rugs in stock on 5 September 2026, coarse northwest Persian Heriz carpets carry a median price of $25,000 against $10,500 for Isfahan, one of the most finely knotted weaves in Persia. Format is part of that gap, because Heriz survive mostly as room size carpets while our Isfahans skew small, and that is exactly the point: size, condition, colour and the quality of the drawing move price far harder than density does. Nobody buys a 1890s Heriz in spite of its knot count. They buy it for the colour and the scale of the geometry, which is what that weave does better than a finer one could.
Where the number genuinely helps is within a single weaving tradition. Comparing two Kashans, or two Kazaks, density tells you something real about the workshop, the time invested and often the period. Comparing a Kazak to a Kashan tells you only that they are different kinds of object, made by different people for different rooms.
What knot counts should you expect?
These are the ranges commonly reported for antique weaving. Treat them as orientation, not specification, because individual pieces sit outside them constantly.
| Type of weaving | Typical range | What it buys |
|---|---|---|
| Tribal and nomadic | roughly 30 to 80 KPSI | Bold geometry, thick wool pile, great durability |
| Village and small town | roughly 60 to 140 KPSI | Recognisable motifs drawn with freedom, strong colour |
| City workshop | roughly 130 to 350 KPSI | Curvilinear floral design, medallions, fine borders |
| Very fine workshop, often part silk | 400 KPSI and above | Pictorial detail, shading, near painterly drawing |
The top band exists because of the foundation rather than the knot. A silk warp can be spun far finer than a wool one, so more of them fit across an inch, so more knots do too. A small silk Isfahan is dense because of what it is built on, which is the argument our foundation guide makes at length.
What matters more than the number?
Four structural details tell you more about a rug than its KPSI, and none of them appear in a listing.
The jufti knot. Also called the false knot, it is tied over four warps instead of two. It covers ground twice as fast and uses half the yarn, and the result is a thinner, less durable pile that wears through sooner. It shows up in some Khorasan weaving and in later commercial production. On the back it reads as knots that look stretched sideways rather than square. A rug is not automatically bad for having them, but you should know before you pay for density you are not getting.
Depressed warps. In many city weaves one warp of each pair is pulled below the other, so the knots stack in two planes. This produces a thick, heavy, dead flat carpet, and on the reverse the knot nodes appear as a single visible row rather than a pair. Kerman, Kashan and above all Bidjar weaving use it; Bidjar is famous for being so densely packed and so heavily wefted that the carpets are difficult to fold and effectively impossible to wear out.
The number of wefts between rows. One weft gives a light, flexible rug typical of tribal weaving. Two is the general standard. Three or more, beaten down hard, gives the weight and flatness of a workshop carpet. This does more to determine how a rug feels underfoot than knot density does.
The wool itself. Hand spun wool from a mountain flock, with its uneven thickness and high lanolin content, takes dye unevenly and ages into the soft tonal variation collectors call abrash. Fine, evenly machine spun yarn at a high knot count can produce a technically superior and completely lifeless rug. This is the single most common trade off between a nineteenth century village piece and a twentieth century workshop copy of it, and it is covered further in our guide to how rug age is determined.
How do you read knot structure at home?
You need daylight and a ruler. Nothing else.
- Fold the rug pile side out and look into the base of the pile along the fold. You will see the knot collars sitting on the warps.
- Check the symmetry. If the two ends of each knot emerge together between one pair of warps, it is symmetric. If one end emerges between the pair and the other outside it, giving the row a slight lean, it is asymmetric.
- Count a square inch on the back in a clean area of the field, and do it in two or three places.
- Compare against the type, not against other types. A hundred KPSI is coarse for a Kashan and unusually fine for a Kurdish tribal rug.
- Look for jufti. Nodes noticeably wider than they are tall, across a whole area rather than in one patch, are worth a second look.
If a seller will not photograph the back of a rug, that is information. On a hand knotted piece the reverse is the honest side, and everything in this guide is read from it. Our own antique rug collection and the type guides under rug weaving types are organised around exactly these distinctions.
The short version
There are two knots. The symmetric one wraps both warps and belongs to Anatolia, the Caucasus and the Kurdish and northwest Persian world; the asymmetric one wraps one and belongs to the Persian city workshops, India and China. Count the nodes across an inch, multiply by the rows down an inch, and you have KPSI. Then treat that number as a description of how finely the design could be drawn rather than as a grade, compare it only against rugs of the same kind, and spend your attention on the wool, the dyes, the drawing and the condition of the foundation instead. Those are what decide whether a rug is worth owning.
Frequently asked questions
What is the difference between the Turkish and Persian knot?
The symmetric or Turkish (Ghiordes) knot loops around both warp threads and brings both ends up together between them, giving a sturdy grip that suits bold geometric drawing. The asymmetric or Persian (Senneh) knot wraps fully around one warp and passes behind the other, so it can be packed more tightly and follow a curved line. The symmetric knot dominates Anatolian, Caucasian, Kurdish and northwest Persian weaving; the asymmetric knot dominates the Persian city workshops, India, China and Turkmen weaving. The names are nineteenth century labels of convenience, not reliable statements of origin.
How do you count KPSI on a rug?
Turn the rug over and work on the back, where each knot appears as a small node. Lay a ruler flat and count the nodes across one horizontal inch, then count the rows of nodes down one vertical inch, and multiply the two. Ten across by twelve down is 120 knots per square inch. Measure in the open field away from the border and away from any repair, and take two or three readings, because density on a hand woven rug drifts as the weaver’s tension changes.
Does a higher knot count mean a better rug?
No. Knot density describes how finely a design can be drawn, much as pixel count describes a photograph. It says nothing about the quality of the wool, whether the dyes were natural, how good the drawing is, or the condition of the foundation. Knot count is genuinely useful when comparing two rugs of the same type, and close to meaningless when comparing across types. Coarse Heriz carpets routinely sell for more than far more finely knotted Isfahans.
What is a good KPSI for an antique rug?
It depends entirely on the type. Tribal and nomadic weaving typically runs about 30 to 80 knots per square inch, village and small town weaving about 60 to 140, city workshop weaving about 130 to 350, and very fine workshop rugs, often part silk, 400 and above. A hundred KPSI is coarse for a Kashan and unusually fine for a Kurdish tribal rug, so always judge the figure against the weaving tradition rather than against an absolute standard.
What is a jufti knot?
A jufti knot, sometimes called the false knot, is tied over four warp threads instead of two. It covers ground roughly twice as fast and uses about half the yarn, and the result is a thinner, less durable pile that wears through sooner. It appears in some Khorasan weaving and in later commercial production. On the reverse it reads as knot nodes that look stretched sideways rather than square.
Can you tell where a rug was made from its knot?
The knot narrows the field but does not settle it on its own. Knot type is a strong regional indicator, and combined with the foundation material, the number of wefts between knot rows, the selvedge and end finishes, and the design vocabulary it becomes reliable. Read on its own it misleads, because the symmetric knot appears well outside Turkey and the asymmetric knot appears well outside Persia.