SPECIAL NOTE: The chart below in some cases uses rough means of calculating an end result. Not all carpet qualities from each of the represented countries have been reported. In cases of raj, these numbers are usually reported in even numbers. In some instances, quality has been placed in a row which is + or - 5 kpsi of what the actual calculation produces.
KPSI: Knots Per Square Inch. If you take a ruler and count knots on one inch of warp and one inch of weft, multiply the two together and your ending number is known as KPSI. KPSI is a standard method of indicating knot density mainly in the US. For photographs on how to assess knot count, click here.
RAJ: Raj are the units of knot density used primarily in Iran typically for tabriz rugs. However, Raj has been known as a point in reference for other carpets as well. It is originally believed that this unit of measure was derived from comparing the length of one standard rolled cigarette to the knots on the reverse of a rug. The way to determine KPSI from RAJ is as follows: ((RAJ/7)*2.54)^2=KPSI
LINE: Line is how the Chinese produce their carpets. The way to derive KPSI from line is as follows: LINE*LINE/144
INDIA 1: As seen in the chart up top, there are two+ units of measure for Indian rugs. One is the traditional knot grid, and the other is square knots. India 1 as marked below refers to the traditional knot grid, of which the conversion is somewhat inaccurate, although more often than not within 10% of true KPSI. For the formula of India 1 KPSI conversion, multiply the numerator and denominator, then divide by 4.
INDIA 2: India 2 refers to India's use of square knots. A square knot is any knot which has been created in such a way to land an equal amount of knots per warp within one inch as there are on the weft per one inch. However, this does not necessarily mean the knot itself is square. An example of this type of carpet would be a "jaipur" rug. For India 2 KPSI conversion, the formula is simply to multiply numerator and denominator for a final KPSI count.
pakISTAN: pakistan knot count is currently being updated. This is a clean calculation, simply multiply numerator and denominator for a final KPSI count.