Denim, decoded: weight, selvedge, and what the numbers mean
Published Oct 13, 2026 · Updated Oct 14, 2026 · By Iris, Pieces & materials editor
The tag on a pair of jeans carries four numbers that actually matter: an ounce weight, a stretch percentage, and two words (selvedge and raw) that describe how the fabric was woven and what was done to it afterward. This note decodes all four.
Ounces: weight per square yard
Denim is quoted in ounces per square yard, and the number sets the personality of the pair. Light denim (10-12 oz) drapes and fades fast; midweight (12-14 oz) is the standard range with enough body to hold a straight leg; heavyweight (14 oz and up) starts almost board-stiff and breaks in over months. Carhartt documents its Relaxed Straight Rugged Flex jeans at 12 ounces — squarely midweight, with the structure a work jean needs. Heavier is not automatically better: a 16-oz pair in a hot climate is punishment.
Selvedge: the finished edge
Selvedge is a weaving method, not a fiber. Shuttle looms, the older, slower kind, weave the fabric as a tube with a self-finished edge, so the seam cannot fray; that edge, with its colored line, is what you fold up at the hem. Uniqlo’s own copy for its Selvedge Straight Jeans describes denim “woven on old-fashioned shuttle loom” with a “signature red ear piping detail,” developed with the Japanese mill Kaihara. Levi’s describes the same technique as creating “a crisp, finished edge” and notes that selvedge denim is heavier and more structured. Shuttle-loom denim is often woven with less tension than modern looms, so it fades with sharper contrast.
Raw, washed, and sanforized
Raw denim has not been washed after dyeing: it is stiff, dark, and it fades where you wear it rather than where the laundry does. Sanforized is the missing step from most raw denim — a mechanical pre-shrinking process applied at the mill so the finished garment moves little in your washer. Unsanforized denim, by definition, has not had that treatment, and it will shrink.
Levi’s 501 Original Shrink-to-Fit jeans are the documented example: raw, non-stretch, unsanforized, with the brand stating shrinkage in the wash of approximately 10% and printing three sizing methods on the product page. The classic method is to buy true to size in the waist and two sizes up in length, soak them on, and wear them until dry; the machine-wash method asks for about an inch more in the waist and three more in the inseam.
Stretch: the percentage that changes everything
Stretch is measured as the percentage of elastane or spandex in the blend. The Uniqlo selvedge pair is 100% cotton — no give at all. Levi’s regular (non-Shrink-to-Fit) 501 Original is 99% cotton with 1% elastane — enough to matter, not enough to feel like performance wear. Carhartt’s Rugged Flex denim runs 85% cotton, 14% polyester, 1% spandex, a work-wear blend where the polyester trades fade quality for abrasion resistance. Our read: above roughly 2% elastane, a jean stops behaving like denim and starts behaving like stretch pants that look like denim — it recovers less over years, and knees and seats bag out.
The behavior table
| Term on the tag | What it actually means | What it changes |
|---|---|---|
| 12 oz (per square yard) | Midweight denim, brand-documented | Holds a straight leg; moderate break-in |
| Selvedge | Shuttle-loom weave with a finished edge | Heavier, more structured, sharper fades |
| Raw | Not washed after dyeing | Stiff, dark, fades with wear |
| Sanforized | Pre-shrunk at the mill | Stable size in the wash |
| 1% spandex | Trace stretch in the blend | Slight give, mostly unchanged hand |
How to choose
Start with the cotton percentage, because it caps everything else: 100% cotton fades best and stretches least; polyester trades fade for durability. Then check whether the denim is sanforized — if the page does not say, assume unsanforized and plan the first wash. Selvedge last: it changes the fading pattern, not the fit.
What we would pick
Uniqlo Selvedge Straight Jeans Levi’s 501 Original Shrink-to-Fit Men’s Jeans Carhartt Relaxed Straight Rugged Flex Jeans
The three cover the range. The Uniqlo Selvedge Straight Jeans are the low-risk entry to selvedge: rigid 100% cotton with the red-line edge. The Levi’s 501 Original Shrink-to-Fit Men’s Jeans are the reference for unsanforized denim — the shrinkage and sizing methods are documented on the product page, so the first wash is a decision rather than a surprise. The Carhartt Relaxed Straight Rugged Flex Jeans are the work end: a documented 12-ounce denim with 1% spandex and a relaxed cut that assumes boots.
Read the cotton percentage before the marketing word, and the shrink warning before both.
The picks
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Uniqlo Selvedge Straight Jeans
The first selvedgeThe entry point to selvedge denim: shuttle-loom cloth developed with the Japanese mill Kaihara, 100% cotton, rigid, with the red-line ear to fold up at the hem. Uniqlo's own copy calls out the 'signature red ear piping detail' — it is the clearest way to see what selvedge means in person before paying several times as much.
- + 100% cotton selvedge with the red-line edge detail
- + Straight cut from waist to hem, no taper to fight
- + Machine wash cold — a low-risk first raw denim
- – No denim weight stated on the product page
- – Rigid cloth needs a break-in period
- – Cold wash and no dry clean means slower fading, by design
Levi's 501 Original Shrink-to-Fit Men's Jeans
The raw referenceThe unsanforized reference pair: raw, non-stretch denim that the brand says shrinks about 10% in the wash, so the fit is yours to control. Levi's documents the sizing methods on the product page — soak them on in a tub and dry them on your body, or buy up an inch in the waist and three in the inseam for machine washing. The straight 501 fit is the baseline every other jean is measured against.
- + Brand-stated ~10% wash shrinkage makes sizing predictable
- + Raw, non-stretch denim fades where you wear it
- + The 501 straight fit is the industry reference point
- – You manage the first wash yourself — soak or size up
- – Button fly is slower than a zip and takes practice
- – Stiff out of the box; break-in is weeks, not days
Carhartt Relaxed Straight Rugged Flex Jeans
The work jeanThe stretch end of the range: a documented 12-ounce cotton-polyester denim with 1% spandex, triple-stitched main seams, and a relaxed cut through the seat and thigh. This is what denim looks like when durability outranks drape — the weight is printed, the stretch is minimal, and the care instructions assume work rather than wardrobe preservation.
- + Documented 12-oz weight — midweight with real structure
- + 1% spandex adds give without changing the hand
- + Triple-stitched seams and reinforced pockets
- – Polyester content dulls the fade versus all-cotton
- – Relaxed workwear cut, not a slim silhouette
- – Tumble-dry-low care instructions work against dark indigo
Comparison
Three ways the numbers land: rigid selvedge, unsanforized raw, and stretch work denim.
| Uniqlo Selvedge Straight Jeans | Levi's 501 Original Shrink-to-Fit Men's Jeans | Carhartt Relaxed Straight Rugged Flex Jeans | |
|---|---|---|---|
| Stretch | None — 100% cotton | None — 100% cotton, non-stretch | 1% spandex (85% cotton, 14% polyester) |
| Selvedge | Yes — shuttle-loom, red-line ear | No | No |
| Pre-shrunk | Not stated — expect some movement | No — unsanforized, ~10% in wash (brand-stated) | Not stated |
| Stated weight | Not stated | Not stated | 12 oz (brand-stated) |
| Wash care | Machine wash cold, no dry clean | Machine wash cold, no dry clean | Machine wash cold gentle, no dry clean |
Prices and availability change — the buttons above check the current listing. Last verified October 2026.
Frequently asked questions
- What does the oz number on jeans mean?
- It is the weight of the denim in ounces per square yard. Roughly, 10-12 oz is light to midweight, 12-14 oz is the standard range, and above 14 oz reads heavyweight. Heavier denim starts out stiffer, holds a crease better, and fades more slowly.
- Is selvedge denim better?
- Selvedge describes how the fabric is woven — on shuttle looms that finish the edge so it cannot fray — not a quality grade. It usually comes in heavier weights and fades with sharper contrast, because shuttle-loom denim is often woven with less tension. It is a construction and a look, not a guarantee.
- How much will raw denim shrink?
- Unsanforized, or raw, denim shrinks in the first wash. Levi's states about 10% shrinkage in the wash for its Shrink-to-Fit jeans, with sizing methods printed on the product page. Sanforized denim is pre-shrunk and should move far less. If a brand does not say, assume some shrinkage and size up.