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What is KPSI, how to Count Knots in Oriental Carpets and Persian Rugs Quality Kerman, Sarouk


What you’re watching is an instructional video on how to count kpsi.  KPSI stands for Knots Per Square Inch, which is one of multiple qualitative measures used by those in the Rug Industry.  This is done by inspecting the reverse side of an oriental rug, and physically counting knot density in one square inch.

In order to count KPSI you’ll need several things.  A hand knotted rug, possibly a pen or pencil to help count fine pieces, and a US quarter or ruler.  KPSI should really an average measure from two or more areas averaged together located closer to the center of a rug.  However for purposes of this video, we’ve isolated just one for quick demonstration.

We take a close look at three pieces to count KPSI.  The first is a Mohajeran Sarouk, from just after  the turn of 1900.  The second rug is a Caucasian piece, probably from the fourth quarter, 19th century.  The last piece is a curveball piece:  A mature semi-antique kerman rug just under 100 years old. 

We used a quarter in this demonstration for 2 reasons. First, they’re convenient.  Secondly, they measure just a fraction under an inch.  When measuring KPSI, it’s best to lean toward the conservative side.  You may also notice you have to bump the count up because one knot may lay half on or off the area you’re measuring.

It’s important to note that higher knot count does not necessarily reflect higher quality.  Although for this video we use much older rugs, knot count is really more for assessing newer, commercially available rugs.  Qualities of rugs are based on many, many factors which can be researched on the main Rug Rag site.


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