How much is the range of weft density in a carpet?

Answer 1

How is width density described in Carpet

In woven carpet that is called Pitch & In tufted carpet it is called "gauge"

Pitch is the number of rows across 27" of weft.. so a 180 Pitch would have 180 rows of yarn across 27 inches or about 6.7 per inch

a 270 pitch is obviously more yarns in the same area so it should be tighter if the yarn size is the same at 10 yarns per inch across the weft

In tufted carpet we measure the spacing from the center of adjacent needles. for example if iis 1/10" between needles we call it "Tenth gauge" of if it's 1/8" between we call it Eighth Gauge..

From loose to tight the most common gauge in Tufting would be 5/32, 1/8, 1/10, 5/64, and the occasional 1/16 gauge machine does exist.