4-Point Fabric Inspection System Explained: Scoring, Formula and Acceptance Limits

The 4-point system is the most widely used fabric grading method in garment manufacturing, standardised as ASTM D5430: each visible fault is penalised 1 to 4 points by its length, and the roll total is normalised to points per 100 square yards so it can be compared with the buyer’s acceptance limit.

Quick reference:

• Scoring: ≤ 3 in = 1 · 3–6 in = 2 · 6–9 in = 3 · > 9 in = 4; holes ≤ 1 in = 2, > 1 in = 4.
• Formula: Points/100 yd² = (Total points × 3,600) ÷ (Cuttable width in inches × Yards inspected).
• Pass mark: set by the buyer. 40 points/100 yd² per roll is often quoted, but brand manuals are usually stricter and fabric-specific.

For the full inspection workflow, defect types and machine options, see our fabric inspection guide (pillar link — add on publishing).

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What is the 4-point system?

It quantifies roll quality with penalty points: longer or more serious faults earn more points, but no single fault can earn more than 4. ASTM D5430 describes it as a numerical grading method based on visual inspection, with criteria and tolerances agreed in advance between buyer and seller.

Why fabric QC teams in Dhaka, Tiruppur, Bangalore or Ludhiana rely on it:

• Simple to train — inspectors only need to measure the fault.
• Normalised to area, so rolls of different width and length can be compared.
• A common language between the fabric store, the mill and the buyer’s QA when raising claims.

The system covers visual faults. Shade, width shortfall and skewing are normally assessed separately unless the buyer manual adds them to the score.

4-point scoring table

Points are based on fault length in either warp or weft direction; holes and openings are scored by their largest dimension.

Fault size	Metric equivalent (approx.)	Penalty points
Up to 3 in	≤ 7.6 cm	1
Over 3 in up to 6 in	7.6 – 15.2 cm	2
Over 6 in up to 9 in	15.2 – 22.9 cm	3
Over 9 in	> 22.9 cm	4
Hole / opening ≤ 1 in	≤ 2.5 cm	2
Hole / opening > 1 in	> 2.5 cm	4

Scoring rules you will commonly find in buyer manuals (always check the manual you are working to):

• Maximum 4 points per fault.
• Continuous faults running along the roll (e.g. a dye streak) are scored per length segment; many manuals cap the points per linear yard.
• Only faults visible under the specified lighting and viewing distance are scored.
• Faults outside the cuttable width (in the selvedge) are usually ignored.

The formula: points per 100 square yards

Points/100 yd² = (Total roll points × 36 × 100) ÷ (Cuttable width in inches × Yards inspected)

• 36 converts width from inches to yards; 100 scales the result to 100 square yards.
• Use the actual cuttable width measured on the roll, not the width on the roll ticket.
• Use the inspected length from the machine’s counter.

Many mills supplying South Asian RMG units invoice in metres. The metric equivalent is:

Points/100 m² = (Total points × 10,000) ÷ (Width in cm × Length in m)

⚠️ The two are not interchangeable: 100 yd² ≈ 83.6 m², so points/100 yd² ≈ points/100 m² × 0.836. Converting in the wrong direction makes the limit about 20% tighter or looser than intended.

Worked examples

Example 1 — single roll (imperial): 120 yd roll, 58 in cuttable width.

Fault	Count	Points each	Subtotal
≤ 3 in	5	1	5
3–6 in	3	2	6
6–9 in	2	3	6
> 9 in	1	4	4
Hole > 1 in	1	4	4
Total			25

(25 × 36 × 100) ÷ (58 × 120) = 90,000 ÷ 6,960 ≈ 12.9 points/100 yd².

Example 2 — metric roll: 100 m roll, 150 cm width, 30 points. (30 × 10,000) ÷ (150 × 100) = 20 points/100 m² ≈ 20 × 0.836 ≈ 16.7 points/100 yd².

Example 3 — evaluating a lot (3 rolls, 58 in width). Assume, for illustration only, a buyer limit of ≤ 28 points per roll and ≤ 20 points lot average.

Roll	Yards	Points	Points/100 yd²	Per-roll result (≤ 28)
1	120	25	12.9	Pass
2	110	18	10.2	Pass
3	95	50	32.7	Fail
Lot	325	93	17.8	Lot average passes (≤ 20)

Lot score = total points ÷ total area: (93 × 3,600) ÷ (58 × 325) ≈ 17.8. Do not take a simple average of roll scores when roll lengths differ. The example also shows why both limits matter: the lot passes on average, but roll 3 still has to be segregated for return or conditional use.

What is an acceptable 4-point score?

There is no universal pass mark — the buyer, brand or purchase contract sets it. 40 points/100 yd² per roll is the figure most often quoted in industry references, but in practice:

• Limits differ by fabric type (e.g. cotton twill/denim vs. synthetics) and are often tighter than 40.
• Most manuals set two limits: per roll and per lot/shipment average.
• Some add conditions such as a maximum number of 4-point faults per roll, no faults in specific zones, or minimum width.

Tip: keep a one-page matrix of limits for every active buyer at the inspection station, and configure it in your inspection software if you use one.

Six practical tips for reliable 4-point results

1. Measure actual cuttable width at several points along the roll.
2. Take length from the machine counter, not the roll ticket.
3. Standardise lighting and machine speed — running too fast hides small faults.
4. Calibrate inspectors regularly by having several people inspect the same reference roll.
5. Flag faults at the selvedge so the cutting room can cut around them; a high score does not always mean rejection if faults are concentrated in a cut-out zone.
6. Keep roll-wise and supplier-wise records for claims and vendor rating — they feed your quality management system.

For knits and stretch fabrics, inspect without stretching the fabric, otherwise the width you record will not match the relaxed width used for markers.

4-point vs. 10-point system

Both penalise faults by length, but the 4-point system normalises to points per 100 yd² so rolls of any size can be compared, while the 10-point system uses a heavier penalty scale and compares total points with roll length. The 4-point system dominates export RMG. The detailed 10-point table should be added from an approved reference if required.

How inspection machines support 4-point grading

An inspection machine gives accurate length, consistent speed and lighting; software and camera systems add automatic fault logging, scoring and reports, reducing manual calculation errors. Reference options (not required):

• C-tex inspection retrofit — adds length/width measurement, quality reports, fault discount tables, supplier claims and grading to existing frames.
• Q-Master AI fabric inspection — industrial camera, defect mapping, custom reports, Open API; published scope is plain single-colour fabric. The page does not state built-in 4-point calculation — confirm with the supplier before claiming it.
• Shelton Vision — real-time defect map with image, type and position.

When you don’t need one: low volumes, a basic frame and well-trained inspectors — a standard scoring sheet and a spreadsheet will do.

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