Single Jersey vs Interlock vs French Terry
Single jersey, interlock and French terry are three of the most widely used knitted fabrics in basics, babywear and sleepwear. They can be knitted from the same cotton yarn, yet they look, feel and perform differently. This guide compares their structure, weight, stretch and warmth, sets out the pros and cons of each, and explains how to choose between them, with particular attention to baby products.
How Each Fabric Is Made
The differences start on the knitting machine. Each structure arranges its loops in a different way, which explains most of what you see and feel in the finished fabric.
Single jersey
Single jersey is knitted on one set of needles, so every loop is pulled through in the same direction. The face shows neat V-shaped columns, the back shows small half-loops, and this imbalance makes cut edges curl.
Interlock
Interlock is a double knit made on two sets of needles: in effect, two 1x1 rib fabrics knitted into each other. Both sides show the same smooth V-columns, and the fabric is thicker, firmer and flatter than single jersey made from the same yarn.
French terry
French terry starts from a jersey-like ground with an extra loop yarn laid in at intervals. The face is flat and smooth, while the back carries soft, uncut loops. Two-thread French terry uses a ground yarn and a loop yarn; three-thread versions add a binding yarn and are usually heavier. When the loops are brushed, the fabric becomes fleece.
Side-by-Side Comparison
The table compares the three fabrics as they are typically made in cotton-rich qualities. GSM ranges and cost notes are general industry guidance, not fixed values; yarn, gauge and finishing can move any fabric outside these bands.
| Feature | Single jersey | Interlock | French terry |
|---|---|---|---|
| Structure | Single knit | Double knit | Single knit with a looped back |
| Face and back | Smooth V-loops on the face; half-loops on the back | The same smooth surface on both sides | Smooth face; soft loops on the back |
| Typical GSM | Typically 120–220 | Typically 170–260 | Typically 200–350 |
| Stretch | Good widthwise stretch; moderate recovery | Moderate stretch; stable, with good recovery | Moderate stretch; firmer than jersey |
| Warmth | Light and cool | Warmer than jersey from the same yarn | Warmest of the three; loops trap air |
| Edge curl | Curls at cut edges | Lies flat | Slight curl |
| Typical uses | T-shirts, bodysuits, summer sleepwear | Babywear, pyjamas, leggings, fitted basics | Sweatshirts, joggers, pyjamas, baby layers |
| Relative fabric cost | Usually the least expensive | Usually higher than jersey | Usually the highest, mainly due to weight |
Pros and Cons of Each Fabric
No fabric is better in every respect. The useful question is which trade-offs suit your product, season and price point.
Single jersey
- Pros: light, breathable and good at draping; economical; the smooth face prints well.
- Cons: edges curl during cutting; prone to spirality if not well finished; less opaque at low weights.
Interlock
- Pros: soft and smooth on both sides; stable and easy to sew; keeps its shape well after washing.
- Cons: heavier and warmer than jersey; less drape; higher fabric cost.
French terry
- Pros: warm yet breathable; the loops feel soft and absorb moisture; gives structure to relaxed shapes.
- Cons: bulkier seams; loops can snag; dries more slowly; usually the most expensive per metre.
Choosing Fabric for Baby Products
Baby products are washed often and worn against sensitive skin, so softness and stability matter more than the GSM figure on a specification sheet. Many buyers also require certified materials, such as OEKO-TEX® Standard 100 or GOTS.
Whatever the fabric, judge it after several washes. Shrinkage, twist, pilling and seam comfort are what parents notice first.
- Bodysuits: interlock for a soft, stable feel in cooler months; single jersey for lighter summer styles; rib for a close, stretchy fit.
- Everyday pyjamas: interlock or single jersey, chosen according to the season and typical room temperature.
- Warmer pyjamas and layers: French terry adds warmth and body without padding, and its looped back feels soft against the skin.
- TOG-rated sleepwear: a TOG value describes the thermal insulation of the finished product, so fabric, layers and any filling must be assessed together.
A Quick Decision Guide
For T-shirts and sleepwear, the decision usually follows the season, the silhouette and the price point.
- Choose single jersey for T-shirts, summer sleepwear and light bodysuits, where breathability, drape and cost matter most.
- Choose interlock for babywear, fitted pyjamas and premium basics that need a smooth, stable fabric on both sides.
- Choose French terry for sweatshirts, lounge sets, cooler-weather pyjamas and baby layers that need warmth and structure.
- If two options seem equal, sample both in the same colour and wash them before deciding.
Single Jersey, Interlock and French Terry at DRU Textile
DRU Textile produces knitted fabrics in Denizli, Turkey, including single jersey, interlock, rib and kaşkorse, with GSM, width and construction agreed for each project. Our two-thread French terry is used in our 1.0 TOG children’s pyjamas: a breathable, flexible two-piece design that suits toilet training and nursery use, made for children who prefer not to sleep in a sleeping bag.
Fabrics are available in cotton, organic cotton, modal, bamboo and blends, plain-dyed or printed with reactive, pigment or digital printing. For baby products we work with OEKO-TEX® Standard 100 and GOTS certified materials; certificate details are shared on request. You can work with us through Custom Fabric Development or Wholesale Roll Fabric Supply, and per-colour and total minimums are confirmed with each quotation.
Frequently Asked Questions
Choose the Right Knit for Your Collection
Tell us about your product, season and target price, and we will suggest suitable fabrics and prepare a project-based quotation.