Women's Denim
Denim sizing hides most of its variation in two numbers brands rarely put on the size label: rise and stretch percentage. Rise (low, mid, high) shifts where the waistband sits relative to your natural waist, so two jackets or jeans in the “same” size can sit inches apart on your body depending on cut.
Stretch percentage matters just as much. A rigid, 100% cotton denim holds its cut measurements; add 2–3% elastane and the same nominal size will fit noticeably closer, because the fabric is doing some of the work a larger size would otherwise do. Brands rarely disclose stretch percentage prominently, but it's usually in the fabric composition line if you look for it.
Denim also tends to relax slightly with wear — rigid denim more than stretch denim — which is why some brands intentionally cut it to fit snug new. None of that is visible from a product photo. Check the composition and rise callouts on the retailer's own page, and treat the size label as a starting point, not a guarantee.
Women's Denim at retailers
Aritzia
THE ‘90S SO-SOFT DENIM JACKET
Aritzia
TONI SHRUNKEN DENIM JACKET
Aritzia
BARKLEY LIGHTWEIGHT DENIM JACKET
Aritzia
THE ‘90S SO-SOFT DENIM JACKET
Aritzia
TONI SHRUNKEN DENIM JACKET
Aritzia
BARKLEY LIGHTWEIGHT DENIM JACKET
Lee Jeans
Womens Premium Removable Fur Collar Denim Jacket
Lee Jeans
Womens Premium Sherpa Lined Aviator Denim Jacket
Lee Jeans
Womens x JCrew Storm Rider Denim Jacket
Lee Jeans
Womens x Feng Chen Wang Full Zip Denim Jacket

Eileen Fisher
Garment-Dyed Organic Cotton Denim Jacket

Eileen Fisher
Garment-Dyed Organic Cotton Denim Jacket

Banana Republic Factory
Flannel Lined Denim Jacket

Banana Republic Factory
Sherpa Collar Denim Jacket

UNIQLO
UNIQLO Women's Barn Short Jacket Denim, Navy, XL
Calvin Klein
Calvin Klein Women's Cinched Peplum Denim Jacket - Green - XL
Calvin Klein
Calvin Klein Women's Relaxed Denim Jacket - Blue - M

Gap
Corduroy-Collar Relaxed Denim Jacket

Gap
Gap × A.P.C. Structured Denim Jacket

Gap
Barrel-Sleeve Icon Denim Jacket