Knot density is the number of knots in a given area of a hand-knotted rug. It is the most common measure of how finely a rug is woven, and it affects the price more than almost any other factor. Our glossary has a short definition of knot density. This guide goes further.
How Knot Density Is Measured
Density is usually given as knots per square inch (KPSI). Some makers use knots per square decimetre, or the number of knots per line along the width and length. They are all measures of the same thing. To compare a quote in one unit against another, convert first.
What Counts as Low, Medium or Fine?
These ranges are a guide only, and makers use different scales:
- Coarse: under about 40 KPSI. Bolder patterns, thicker pile, lower cost.
- Medium: about 40 to 100 KPSI. The standard range for most commercial hand-knotted wool rugs.
- Fine: about 100 to 200 KPSI. Sharper curves, detailed floral and pictorial designs.
- Very fine: above 200 KPSI, mostly in silk or silk-and-wool rugs.
How to Count Knots
Turn the rug over. On the back, each knot shows as a small bump or loop. Count the knots along one inch of the width and along one inch of the length, then multiply the two. A rug with 8 knots across and 10 down has about 80 KPSI.
Why Density Affects Price
A denser rug has more knots, and every knot is tied by hand. A rug with twice the density takes roughly twice as long to weave. That labour is the main driver of price.
Higher Is Not Always Better
Density affects the detail a design can show. A bold geometric pattern looks fine at a medium density. A curved floral design needs a finer weave to look crisp. Pile height and yarn quality matter just as much for durability, so look at all three, not at the knot count alone. See pile height.
Density and Other Constructions
Knot density applies only to hand-knotted rugs. Hand-tufted rugs are measured by the stitch density and pile height, and flatweaves by the number of picks per inch. See the difference between hand-knotted and hand-tufted rugs.
What to Ask a Supplier
Always request the density in writing and in a stated unit, with the pile height and the yarn. Browse our hand-knotted wool rugs or ask for samples.
