China, India and Pakistan each use their own unique system for grading rug quality by knot count. Handmade rugs from any country (except China) are usually graded by knots per square inch.

In general, the most finely knotted rugs are the most expensive, principally because of the greater amount of material used and the greater time taken in the weaving process. The following is an approximate guide to classification of knot density:

• up to 30 knots per sq. in. = very coarse


• 30 – 60 knots per sq. in. = coarse


• 130 – 160 knots per sq. in. = fine


• 160 – 290 knots per sq. in = very fine


• Over 290 knots per sq. in = extremely fine

Pile

The height of the pile is not an indication of the rug’s quality; the finest rugs very often have the shortest pile – it is more often an indication of the region that it was made in. Nomad rugs from cold regions will generally have a higher pile than those woven in desert conditions.

Pile height can be defined as follows:

1/8" = low or flat
1/8" to 3/8" = medium high
3/8" to 3/4" = high
Over 3/4" = extremely high/long