Single Jersey vs Interlock vs Rib Knit: Which Cotton Fabric Is Best for Kids' Clothes? (A Maker's Guide)

Short answer: single jersey is the thin, light, breathable knit used for everyday cotton T-shirts for kids, and it is the best pick for Indian summers. Interlock is a double knit, smooth on both sides, thicker and more stable, which makes it the better fabric for full sleeve night suits, AC rooms and cooler months. Rib knit is the stretchiest of the three and belongs on necklines, cuffs and fitted pieces. French terry, a looped knit, is the one to choose for joggers and winter layers.

We knit, cut and stitch kids clothes in our own unit in Tiruppur, the knitwear town of Tamil Nadu, and these three fabric names come up every time we plan a new style. This guide explains each knit in plain language, shows you how to identify it in a shop in under a minute, and tells you which one to buy for which garment, season and child.

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Mid Lavender Super Soft Cotton T-Shirt (single jersey)

₹499

Light Yellow Super Soft Cotton T-Shirt (single jersey)

₹499

The Football Collection: Blue Co-ord Set (240 GSM French terry)

₹799

See all cotton T-shirts for kids

What is a knit fabric, and how is it different from a woven one?

Every cotton garment your child wears is either knitted or woven. A woven fabric, such as the poplin in a school shirt or the seersucker in a summer co-ord, is made by crossing two sets of threads at right angles, like a mat. A knitted fabric is made from a single yarn pulled into rows of loops, each row hanging from the one above it. The Textile Research Lab at Pratt Institute puts it simply: knitting involves a single thread that forms loops, which are then connected in rows or rounds.

Those loops are why knits stretch and spring back, and why almost everything a toddler wears all day (T-shirts, night suits, joggers, vests, leggings) is a knit. They are also why knits behave differently in the wash. Cotton Incorporated, the research body of the cotton industry, notes in its technical bulletin on knitted fabrics that knits of all constructions are inherently more prone to shrinkage than wovens. A loop can be pulled longer or squashed shorter; a woven grid cannot move nearly as much.

Inside the knit family, the way the loops are arranged gives you three basic structures that matter for kids clothes: single jersey, rib and interlock. Almost every other knit you will see on a label (pique, French terry, fleece, waffle) is a variation built on one of these.

What is single jersey fabric?

Single jersey is knitted on one set of needles, so every loop faces the same way. Pratt describes it as a fabric knitted with a single yarn on a single set of needles. The result is a fabric with two different faces:

• The front (face) shows neat little vertical V shapes, like tiny columns of plaits.
• The back shows small horizontal bumps and loops. It looks rougher and slightly duller.

Because it is a single layer, single jersey is the lightest and most breathable of the three knits. That is why it is the standard fabric for kids T-shirts across the world. In a study of a typical 100% cotton single jersey knitted from 30s combed ring-spun yarn, Cotton Incorporated measured weights between about 135 and 176 grams per square metre depending on how the fabric was finished (its Guide to Improved Shrinkage Performance, Table I). If grams per square metre is new to you, our guide to what GSM means in fabric explains it with examples.

What single jersey is good at

• Breathability. One thin layer lets body heat and sweat escape fast, which matters in a 38°C Chennai afternoon or a crowded school bus.
• Drape and softness. It falls softly over the body and does not feel stiff, which suits relaxed and dropped-shoulder fits.
• Printing. The smooth face takes screen prints and other prints well, which is why most printed kids T-shirts are jersey.
• Price. It uses less yarn per metre than a double knit, so it is the most economical knit for everyday clothes.

Where single jersey falls short

• The edges curl. Cut single jersey rolls at the edge. The University of Kentucky Cooperative Extension notes that jersey looks different on the reverse side and its edges tend to curl. In a finished garment this is controlled by hems and binding, but a badly finished hem will flip up.
• Twisting side seams. Single jersey knitted from a single ply yarn tends to torque, or twist, during wet processing, as Cotton Incorporated notes in its knit processing bulletin. If the factory has not controlled this, the side seam of a T-shirt slowly swings round to the front after a few washes. This is one of the clearest quality signals you can check on a T-shirt you already own.
• Less warmth. One thin layer holds little warm air, so jersey alone is not enough for a December night in Delhi.

What is rib knit fabric?

Rib knit is made on a machine with two sets of needles, and the loops alternate between the front and back of the fabric in columns. This creates the raised vertical lines you can see and feel on the neckband of a T-shirt. Pratt describes rib as having vertical textured lines across the fabric and notes that rib knits do not roll and stretch much more across their width than jersey does.

That stretch is the whole point of rib. The Kentucky extension guide notes that rib knits may stretch 100 percent in the crosswise direction, meaning a 10 cm (4 inch) strip can be pulled to about 20 cm (8 inches) and still return to shape. In garment terms, rib is described by its repeat: 1x1 rib (one column up, one column down, fine and smooth) and 2x2 rib (two up, two down, chunkier and more visibly ridged).

Where you will find rib in kids clothes

• Necklines. The band around a T-shirt collar is almost always rib, because it has to stretch over a child's head and snap back without sagging. Our single jersey T-shirts use a rib neck band for exactly this reason.
• Cuffs and hems on sweatshirts and joggers. Ribbed cuffs keep sleeves from sliding over little hands and stop cold air getting in. Our Dino sweatshirt and jogger set, for example, pairs a French terry body with ribbed cuffs.
• Fitted pieces. Rib vests, leggings and fitted tops for girls are often full rib, usually with a little elastane (Lycra) added for extra recovery.

What to watch for: a rib neckband that has gone wavy or flared after a few washes is a sign of a low quality rib or a band that was stitched on too loose. A good neck rib lies flat and hugs the neck without leaving a red mark.

What is interlock fabric?

Interlock is also knitted on two sets of needles, but in a way that locks two layers of loops together so that both sides look the same. Pratt notes that interlock can be identified by its identical appearance on both sides, and that it is thicker and a little less stretchy than regular jersey. Think of it as two very fine jerseys knitted back to back, with the rough sides hidden inside.

The Kentucky extension guide describes interlock as lightweight and drapable, slightly heavier than jersey, with edges that do not curl. For a parent, that translates into four practical points:

• Smooth on both sides. There is no rougher reverse face against the skin, which is why interlock is widely used for babywear and sleepwear.
• A little warmer. Two locked layers trap more still air than one, so interlock feels cosy in an air conditioned bedroom or on a cool night without the weight or sweat of fleece.
• More stable. It holds its shape, does not roll at the edges and hangs neatly, so full sleeve sets look tidy for longer.
• Costlier to make. It needs more yarn and slower knitting than single jersey, so a well made interlock garment usually costs more than a jersey one of the same size.

This is why our Hippo Cuddle night suit and most of our full sleeve PJ sets are cut from premium interlock cotton. They are designed for the child who kicks off the blanket in an AC room at 2 am: the long sleeves and the slightly thicker double knit keep arms and legs covered and comfortable even when the blanket is on the floor. If sleep comfort is your main concern, our guide to safe fabric for children's sleepwear goes deeper.

Single jersey vs interlock vs rib: how do they compare?

Here is the comparison we use when deciding which fabric a new style should be made in. French terry is included because it is the fourth knit most parents meet, in joggers and sweatshirts.

Sources for structure and stretch: Pratt Institute Textile Research Lab; University of Kentucky Cooperative Extension. French terry weight is from Gozi's own range.

How can you tell jersey, interlock and rib apart in a shop? (The 60-second test)

You do not need a lab or a magnifying glass. These are simple hand checks that anyone in the trade uses to tell knits apart. Try them on any garment in a shop or in your child's cupboard.

1. Turn it inside out (10 seconds). If the inside looks rougher and bumpier than the outside, it is single jersey. If the inside looks exactly like the outside, it is interlock. If both sides show raised vertical lines, it is rib. If the inside is covered in small soft loops, it is French terry.
2. Look at a raw edge (10 seconds). Check inside a seam allowance or under a pocket. Jersey edges roll; interlock and rib edges lie flat.
3. Stretch it across the chest (10 seconds). Rib pulls out a long way and snaps back hard. Jersey stretches easily. Interlock stretches less and feels firmer and springier.
4. Hold it up to the light (10 seconds). Single jersey lets more light through. Interlock is noticeably more opaque, which also means less show-through with light colours.
5. Check the side seam (10 seconds). On a jersey T-shirt, the side seam should run straight down from the armpit to the hem. On a garment that has been washed a few times, a seam that has swung towards the front is the twisting described above.
6. Feel the neckband (10 seconds). Stretch the rib collar over your hand and let go. It should spring back fully and lie flat, with no ripples.

Which knit fabric is best for which kids garment?

The right knit depends on what the garment has to do, not on which fabric sounds most premium. This is how we match fabric to garment in our own range, and how we would advise any parent buying from any brand.

If you are building a winter wardrobe, French terry has its own deep dive: what French terry is and how it compares with fleece. Our cotton joggers and track pants for kids are 240 GSM French terry, and the Football Collection co-ord sets use the same fabric for a T-shirt and shorts that keep their shape.

Is interlock fabric for summer or winter?

This is a common question about interlock in India, and the honest answer is: both, depending on where your child is wearing it.

• Summer indoors with AC or a cooler: yes. A full sleeve interlock night suit is ideal for a bedroom at 22 to 24°C, where a thin jersey set can leave a child cold by early morning.
• Summer outdoors in heat and humidity: no, for most children. Choose single jersey. Interlock is breathable cotton, but its double layer holds more warmth and dries a little slower than jersey.
• Monsoon: yes for night wear and indoor days, especially in AC or fan rooms that feel damp and cool.
• Winter in South and West India: yes, as everyday nightwear on its own.
• Winter in North India: yes as a base layer under a blanket or a sweatshirt, but not as the only layer on a cold night. Our post on keeping kids warm in cotton night suits has a layering plan.

Which knit shrinks the most, and how do factories stop it?

Shrinkage is the biggest complaint parents have about cotton knits, and it is mostly decided in the factory before the garment is ever sold. Here is what happens and what the research shows.

During dyeing and drying, a knit fabric is pulled lengthwise through machines. The loops are stretched long and narrow. When you wash and especially tumble dry the garment, the loops relax back to their natural shape: shorter and wider. Cotton Incorporated notes that if a garment is tumble dried, all of its remaining shrinkage will appear, and that one cycle can remove around 90% of the total shrinkage available. That is why a T-shirt can lose most of its shrinkage in the first wash and then stay steady.

The table below comes from Cotton Incorporated's tests on 100% cotton knits after five home washes with tumble drying. It shows how much the finishing route changes the result. The figures are for those specific test fabrics, not every garment, but they show the pattern clearly.

Source: Cotton Incorporated, ISP 1009 Guide to Improved Shrinkage Performance of Cotton Fabrics, Tables II and III (5 home launderings, tumble dried).

Three things stand out for parents:

1. Finishing matters more than the fabric name. The same interlock went from 15% length shrinkage to 5% depending on how it was processed. A 15% loss on a 40 cm (about 16 inch) night suit top is 6 cm, enough to turn a perfect fit into a crop top. That is why two night suits labelled 100% cotton interlock from different makers can behave completely differently.
2. Compacting is the key step. Compacting presses the knit lengthwise to push the loops back towards their relaxed shape before the fabric is cut. Cotton Incorporated defines it as using compressive forces to shorten the fabric and reduce length shrinkage. It is a common finishing step in knit processing, and it is the main reason a good T-shirt keeps its length.
3. Interlock is harder to stabilise in width. A study presented at the 2012 Beltwide Cotton Conferences by researchers at Alexandria University tested six knit structures and found that interlock fabrics tend to shrink more widthwise than fine rib and single jersey, while fine rib changed least in length. So with interlock, check the chest width after the first wash as well as the length.

The same study found that adding Lycra to single jersey reduced its shrinkage, and that cotton and polyester blended interlock was more stable than 100% cotton interlock. Stability is not the only thing that matters on a child's skin, though, which is why we stay with pure cotton and control shrinkage through finishing instead. Our post on polyester vs cotton for kids explains that choice.

If you want to see where compacting, dyeing and checking fit into the whole journey from yarn to finished garment, our step by step guide to how kids T-shirts are made in Tiruppur walks through every stage.

Does the yarn matter as much as the knit?

Yes. The knit structure decides how a fabric behaves; the yarn decides how it feels and how long it lasts. A single jersey from coarse carded yarn and a single jersey from fine combed yarn are the same structure but completely different T-shirts. Combed yarn has the short fibres removed, so it is smoother, stronger and pills less. Our guide on combed cotton and super combed cotton explains the difference.

Finishing matters too. Our T-shirts are single jersey that has been biowashed, an enzyme finish that removes loose surface fibres so the fabric feels softer and resists pilling. Colour is another layer of quality again, covered in our post on why kids clothes fade.

A useful way to think about it: knit (jersey, rib, interlock, terry) tells you the shape of the fabric, GSM tells you how much of it there is, yarn (combed, carded, count) tells you how good each thread is, and finishing (compacting, biowash, dyeing) tells you how it will behave after you take it home. A label that tells you all four is a label from someone who knows what they are making.

How should you wash each knit so it lasts?

All four knits are cotton, so the basics are the same, but each has one weak point worth protecting.

Because tumble drying releases all of a knit's remaining shrinkage at once, line drying is the gentlest option for every knit. For hard water, stains and colour care, see our full guide to washing and caring for cotton clothes.

What should you look for on the label or product page?

Most kids clothing labels in India say only 100% cotton. That tells you the fibre, not the fabric. When you are comparing two garments online, look for these words in the description, and treat their absence as a question to ask:

• The knit name: single jersey, interlock, rib, French terry or fleece. A brand that names the knit has thought about it.
• GSM for heavier pieces like joggers and sweatshirts.
• Yarn type: combed or super combed is better than unspecified.
• A shrinkage or pre-shrunk statement, or a finish like compacted or biowashed.
• Trims: rib neck band, ribbed cuffs, covered elastic.

We name the knit in our product descriptions for this reason: our T-shirts say single jersey, our full sleeve night suits say interlock, our joggers and Football Collection co-ords say 240 GSM French terry. Browse our cotton T-shirts for kids or the interlock night suits and PJ sets and you will see the fabric named on every page.

Frequently asked questions

Is single jersey 100% cotton?

Not always. Single jersey is a knit structure, not a fibre, so it can be knitted from cotton, polyester, viscose or blends. Check the fibre content separately. All Gozi single jersey T-shirts are 100% cotton.

Is interlock better than cotton?

This question mixes two things. Cotton is the fibre; interlock is the way it is knitted. Cotton interlock is simply cotton knitted as a double knit. It is not better or worse than cotton single jersey, just thicker, smoother on both sides and slightly warmer, so it suits different garments.

Is interlock fabric good for babies?

Yes. Its smooth surface on both sides means no rougher face against the skin, it stretches gently over a baby's head and limbs, and it holds a little warmth for AC rooms. In very hot weather without air conditioning, a soft single jersey may be more comfortable.

Which is softer, jersey or interlock?

From the same yarn, interlock usually feels smoother and more substantial, while jersey feels lighter and more fluid. Softness depends just as much on the yarn and finish: a biowashed combed cotton jersey can feel softer than an unfinished interlock.

Does rib knit fabric shrink?

All cotton knits can shrink. In the 2012 Beltwide study, fine rib changed least in length of the structures tested. The bigger risk with rib is losing its snap, so dry rib bands flat or folded rather than hanging them by the band.

Why does my child's T-shirt side seam twist after washing?

Single jersey knitted from a single yarn tends to torque during wet processing. If the fabric was not finished and cut to control this, the seams drift towards the front after washing. It is a manufacturing issue, not a washing mistake.

Which knit is best for Indian summers?

Single jersey in combed cotton for daytime, with rib only at the neck. Save interlock for AC bedrooms and French terry for cooler evenings and winter.