A rug specification sheet is the most important document in any custom rug transaction. It defines exactly what you are buying, how it is made, and what performance characteristics to expect. Yet many designers and buyers gloss over spec sheets because the terminology feels technical. This guide breaks down every standard field so you can read any spec sheet with authority.
Construction Method
This field tells you how the rug is made. The primary categories are hand knotted, loom knotted, hand tufted, hand woven (flatweave), and machine made. Each method produces a fundamentally different product. Hand-knotted and loom-knotted rugs are the most durable and valuable. Hand-tufted rugs use a tufting gun to push yarn into a canvas backing, which is faster but less durable. Flatweaves have no pile at all. Machine-made rugs are produced on power looms with no handwork involved.
At Kapetto, every rug is either hand knotted or loom knotted, which means genuine artisan construction with decades of functional life.
KPSI (Knots Per Square Inch)
KPSI is the density measurement for knotted rugs. It indicates how many individual knots occupy one square inch of the rug's surface. Higher KPSI means finer detail, tighter construction, and generally greater durability. A rug at 60 KPSI is a solid everyday piece. At 100 KPSI, you are looking at fine craftsmanship. Above 200 KPSI, you are in the realm of museum-grade work.
Be cautious with KPSI claims that seem unusually high for the price point. A genuine 200 KPSI hand-knotted rug in silk takes months to produce and costs accordingly. If the spec sheet claims high density but the price is low, the measurement method may differ from industry standard, or the rug may be hand tufted rather than knotted. For a deeper understanding, see our rug glossary.
Fiber Content
This field lists the materials used in the pile (the surface you touch) and sometimes the foundation (warp and weft threads). Common pile fibers include:
- New Zealand wool. Dense, resilient, naturally stain resistant. The industry standard for high-quality knotted rugs.
- Cashmere. Exceptionally soft with a luxurious drape. Lower resilience than wool, best in low-traffic spaces. Kapetto's cashmere pile is 15mm for maximum softness.
- Silk. High sheen, fine detail capability. Delicate and best used as an accent or in very low-traffic areas.
- Viscose/art silk. A plant-based fiber that mimics silk's sheen at a lower cost. Less durable and prone to water damage.
- Jute/hemp. Natural fibers used in flatweaves and casual rugs. Durable but coarse underfoot.
The foundation is typically cotton (stable, does not stretch) or sometimes wool (more flexible, used in traditional tribal rugs).
Pile Height
Pile height is measured in millimeters from the backing surface to the top of the fiber. Low pile (5 to 8mm) is flat and firm, ideal for high-traffic areas and under furniture with casters. Medium pile (9 to 14mm) balances comfort and practicality. High pile (15mm and above) is plush and luxurious but shows footprints and furniture indentations more readily.
Pile height directly affects how a rug feels, how it traps dirt, and how it interacts with doors and transitions. Always cross-reference this number with door clearance measurements from your site survey.
Dimensions and Shape
Spec sheets list dimensions in both imperial and metric formats. Pay attention to the tolerance range, which is the acceptable deviation from the stated size. Handmade rugs are not manufactured to machine precision. A standard tolerance of plus or minus 2% means a 9x12 foot rug could measure anywhere from approximately 8'10" x 11'10" to 9'2" x 12'3". This is normal and expected for genuine handmade construction.
Color Reference
Colors on spec sheets are typically indicated by Pantone codes, proprietary dye codes, or descriptive names with a physical swatch reference. Never evaluate color from a digital image alone. Screens vary wildly in color accuracy. Always request a physical sample or swatch from Kapetto's custom program before approving color for production.
Weight (GSM or oz/sq yd)
Rug weight is expressed in grams per square meter (GSM) or ounces per square yard. Heavier rugs generally feel more substantial and lie flatter on the floor. A lightweight flatweave might be 1,500 GSM. A dense hand-knotted wool rug runs 3,500 to 5,000 GSM. A thick cashmere rug can exceed 5,000 GSM. Weight also matters for shipping estimates and whether the rug needs a pad to prevent movement.
Colorfastness and Performance Ratings
Professional spec sheets include colorfastness ratings (resistance to fading from light and washing), abrasion resistance (Martindale or Wyzenbeek cycles), and sometimes flammability ratings for hospitality applications. These ratings determine whether a rug is suitable for commercial spaces, outdoor-adjacent areas, or rooms with significant natural light.
What to Do When a Spec Sheet Is Incomplete
If a manufacturer cannot provide a complete spec sheet, that is a red flag. Request the missing information before proceeding. Every field described above represents a measurable, verifiable characteristic. Vague language such as "premium materials" or "high quality construction" without specific data points should be met with skepticism. A credible manufacturer like Kapetto provides full specifications on every product in the resource library.
