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v1.0 · 2026

The RUG Index
Grading Standard

The first standardized, reproducible formula for valuing hand-knotted rugs. Accepted by insurance carriers, estate courts, and certified appraisers.

The Formula

Five pillars. One number.

Every RUG Index valuation is produced by the same reproducible formula — no subjective judgment, no hidden factors.

Core Formula
base_sqft × origin_mult × material_mult × age_mult × condition_mult × kpsi_mult
= resale_midpoint ± 20%
Resale Value
× 1.0
Fair market value for private resale or dealer purchase
Retail Replacement
× 2.2
Cost to replace at retail — used for insurance policies
Auction Estimate
× 0.75
Expected hammer price at public auction
Insurance Value
× 2.6
Full replacement cost including dealer premium and sourcing
The Five Pillars

Each factor, explained

01
Origin & Region Multiplier
Where a rug was made is the single strongest driver of value. Persian workshop cities like Tabriz, Isfahan, Kashan, and Nain command the highest multiples. Tribal and village rugs carry lower multipliers but have their own collector premiums.
Persian Workshop 3.2×
Persian Tribal 2.8×
Persian Village 2.4×
Turkish Fine 2.4×
Caucasus 2.4×
Silk (any) 3.0×
Afghan/Pakistani 2.0×
Indian Fine 1.8×
Chinese 1.5×
Machine-made 0.8×
02
Material Quality Multiplier
The fiber content of both pile and foundation. Pure silk commands the highest premium. Hand-spun wool with natural dyes is valued above machine-spun. Synthetic fibers carry the lowest multiplier.
Pure Silk 2.5×
Silk Highlights on Wool 1.8×
Fine Wool 1.0×
Wool/Cotton Blend 0.7×
Synthetic 0.4×
03
Age & Provenance Multiplier
Age is verified by wool oxidation, dye analysis, and structural examination. Documented provenance — auction records, purchase receipts, prior appraisals — adds measurable premium above undocumented pieces of equal age.
Antique 100+ years 2.8×
Semi-antique 50–99 years 2.0×
Vintage 25–49 years 1.4×
Modern 10–24 years 1.1×
New 1.0×
04
Condition Grade
The most variable factor and the one most open to manipulation. The RUG Index uses a six-point condition scale with specific, observable criteria for each grade. Pile height, structural integrity, repair history, and dye stability are all assessed.
GradeLabelMultiplierCriteria
A+Excellent1.00×No visible wear, no repairs, full pile, original condition
AVery Good0.85×Minor even wear, no repairs, pile 90%+ of original
BGood0.70×Light wear in traffic areas, minor repairs, some fading
CFair0.55×Moderate wear, visible repairs, significant fading
DPoor0.35×Major damage, extensive repairs, structural compromise
05
Knot Density (KPSI) Multiplier
Knots per square inch determines the fineness of the weave and the labor investment. Ultra-fine silk rugs can exceed 1,000 KPSI. Coarser tribal rugs may have fewer than 40 KPSI. Both can be valuable — but the density factor is applied accordingly.
Ultra-fine 500+ KPSI 3.0×
Fine 200–499 KPSI 2.0×
Medium 80–199 KPSI 1.2×
Coarse 40–79 KPSI 0.8×
Tribal <40 KPSI 0.6×
See the standard in action

Use our free valuation tool to apply the five-pillar formula (see also how the five-pillar standard works in practice) to your own rug. No account required.

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