Single Jersey vs Interlock: Knit Structure Comparison

Single jersey and interlock are the two knit structures that most garment programs meet first, and they look deceptively similar on a swatch card. They are not variants of each other. Single jersey is knitted on one needle bed, curls at the edges and drapes with a fluid, lightweight hand; interlock is knitted on two needle beds in lockstep, lies flat, and runs thicker and more stable. Choosing between them changes weight, recovery, cutting behavior and garment use more than any finish applied afterward.

Our partner mills in Wenzhou run knit programs alongside its 300-loom weaving floor, with a 7-day sampling gate before every custom run, and structure selection is the first line on those specs. This guide compares the two structures on the properties buyers actually specify, and shows where each one wins in a collection.

How the structures differ at the machine

Single jersey is made on one set of needles, producing a fabric where the face shows plain knit loops and the back shows the loop heads as a subtle purl ridge. Because only one bed is active, the fabric is asymmetric through its thickness, and that asymmetry is why cut edges roll toward the face. Interlock knits two plain fabrics simultaneously on opposed needle beds, bonded into one cloth that shows knit loops on both faces. The double construction roughly doubles the yarn input per square meter at the same gauge, and both faces being identical is what makes the fabric lie flat.

The consequence chain is direct: more yarn means more weight and less transparency; two interlocked layers mean higher dimensional stability and better recovery; symmetric structure means no curling at the cutting table. Buyers who want the formal terminology for these and other fabric constructions will find them standardized in ASTM D4850, the standard terminology relating to fabrics and fabric test methods, which is the reference worth citing when a spec needs to name structures unambiguously.

What each structure is like to specify and cut

Single jersey suits garments that move and breathe: tee bodies, dresses, lightweight layering. Its curling edges are the production consideration, managed by cutting slightly larger allowances, using spreaders, or stabilizing with tape on long edges, and by allowing the fabric to relax overnight before cutting, since the structure relaxes after roll tension. Interlock suits garments that need structure without woven stiffness: polos with body, skirt panels, loungewear with weight, and baby garments where flat, stable fabric and no curl matter. Interlock also takes prints and finishes more evenly because both faces behave the same.

Weight planning differs too. At the same gauge and yarn, interlock runs close to double the grams per square meter, so a program moving from 180 gsm jersey to an equivalent interlock look lands nearer 300 gsm, with all the cost and drape implications that follow. GSM conversions between systems are handled in our GSM to oz guide. Structure also interacts with the failure modes covered in our spirality and needle line defects guide: single jersey is the structure most exposed to spirality when yarn twist is unbalanced, while interlock’s balanced construction suppresses it.

Structure comparison on spec lines

Video: fabric to garment effect

Seeing the same fabric on the body makes the structure difference obvious faster than any spec sheet. Custom structures from our performance knit program start with a sample gate at 7 days, with gauge, yarn and structure locked before bulk knitting.

Frequently asked questions