Yes, bamboo fabric shrinks, often more than cotton, because most of it is bamboo viscose. Our viscose knit records show a median 9% length shrinkage. Why bamboo shrinks, the dryer and cold water, blends and bamboo lyocell, how factories control it and how to wash bamboo.
At a glance
9%viscose median
14%+worst tenth
Dryerbiggest risk
Coolwash, dry flat
Yes, bamboo fabric shrinks, and it can shrink more than cotton. Most bamboo clothing and bedding is bamboo viscose (rayon), and viscose is the fibre that shrinks most of all common fibres. It absorbs a lot of water, swells, loses strength when wet and relaxes. In our finishing records, viscose knit shrank a median 9% in length after the wash test, against 6% for cotton and 3% for polyester. Washed cool and dried flat or on low heat, bamboo garments keep close to their size; washed hot and tumble dried, they can shrink noticeably and twist out of shape.
This guide explains why bamboo fabric shrinks, how much, whether it shrinks in the dryer or in cold water, how bamboo blends and bamboo lyocell behave, how factories reduce shrinkage, how to wash bamboo so it does not shrink, and how to stretch it back if it has. It draws on our dye-house finishing records of viscose, lyocell and cotton knits.
Why bamboo fabric shrinks
Bamboo viscose is regenerated cellulose, made by dissolving bamboo pulp and re-forming it as fibre. Its structure is less ordered than cotton’s, so water gets in easily. Three things happen in the wash:
- Swelling: the fibres absorb water (moisture regain about 13%, much more when soaked) and thicken, pulling the yarns and fabric together.
- Relaxation: knit fabric is stretched lengthwise in processing; when wet and tumbled, the loops relax back and the fabric shortens.
- Weak wet fibre: wet viscose loses much of its strength, so it distorts and settles in a smaller, denser shape.
Heat and agitation speed all three up, which is why hot washes and tumble dryers cause the most shrinkage. See does rayon shrink for the fibre in detail.
How much does bamboo fabric shrink?
In our finishing records of 164 viscose knit batches, the median length shrinkage after the wash test was 9%, the worst tenth shrank 14% or more, and only 23% of parts stayed within the usual 5% shrinkage limit. Light viscose parts also gained a median 17.5% in weight after washing, because the fabric pulls together. Bamboo viscose is the same fibre and behaves the same way. Width usually shrinks much less than length.
In practice, a well-finished bamboo garment washed cool may lose only 2–4% in its first wash, while a poorly finished one washed hot and tumble dried can lose 10% or more.
Does bamboo shrink in the dryer?
Yes, the dryer is the biggest risk. Heat, moisture and tumbling together drive swelling and relaxation, and the weak wet fibre settles smaller. Bamboo sheets, pyjamas and T-shirts dried on high heat often come out shorter, slightly thicker and sometimes twisted. Line drying, flat drying or a low, short tumble keeps shrinkage to a minimum.
Does bamboo shrink in cold water?
Much less than in hot water, but some relaxation still happens in the first wash, because water alone lets the stretched loops relax. A cold, gentle wash followed by line drying usually limits shrinkage to a small amount, and later washes change the size very little.
Bamboo blends and bamboo lyocell
| Fabric | Shrinkage tendency | Why |
|---|---|---|
| 100% bamboo viscose | High | Viscose swells and relaxes; median 9% in our viscose records |
| Bamboo viscose + spandex | High but often heat set | Heat setting stabilises; heat in dryer weakens spandex |
| Bamboo-cotton blend | Medium to high | Cotton shrinks a median 6%; viscose more |
| Bamboo-polyester blend | Lower | Polyester holds the structure; PV blends median 4% |
| Bamboo lyocell | Medium | Stronger fibre; lyocell blends median 7% |
See shrinkage by fibre for all fibres.
How factories reduce shrinkage in bamboo fabric
- Gentle wet processing: mild scour at 70–80°C and dyeing at about 60°C, with careful machine speed so the weak wet fabric is not stretched.
- Heat setting for bamboo-spandex blends before dyeing.
- Overfeed drying: the fabric is fed into the dryer with extra length so it is not pulled long.
- Compacting: pushes the loops back together in length.
- Wash testing before delivery to check length, width and weight.
We do nothing special for lyocell or viscose. They are dyed and finished the normal way. After the stenter we check the parameters. If the length has grown or the width has come down, or the fabric needs some other correction, we set the compactor to adjust for it and then run the fabric.
Even so, viscose keeps relaxing in the customer’s wash, which is why it remains the hardest fibre to keep on size. See the 100% viscose knit dyeing process.
Common mistake: washing new bamboo sheets on a hot cycle and tumble drying them on high “to pre-shrink them”. They do shrink, but unevenly, and the hot, rough cycle also weakens and pills the surface. Wash them cool and line dry instead; the small first-wash shrinkage is usually allowed for in the sizing.
How to wash bamboo so it does not shrink
- Wash cold or at 30°C on a gentle or delicate cycle.
- Turn garments inside out and use a mesh bag for small items.
- Use mild liquid detergent; avoid bleach and heavy softener.
- Do not wring; use a low spin or press water out gently.
- Line dry or dry flat; if you must tumble, use low heat and remove while slightly damp.
- Iron on low to medium heat if needed.
Bamboo sheets and towels
Bamboo bed sheets are usually woven sateen or twill, and woven viscose shrinks mainly in the first few washes, often a few percent in length and width. Good sheet makers size them with a little extra to allow for this. Bamboo towels are usually blended with cotton for strength; the blend shrinks a little and settles after a few washes. Both last longer and stay softer when washed at 30–40°C and dried on low.
Why the first wash matters most
Most of the shrinkage in a bamboo garment happens in the first one to three washes, as the stresses put into the fabric during knitting, dyeing and finishing relax. If those first washes are cool and gentle, later washes change the size very little. If the first wash is hot with a hot tumble dry, the garment can shrink more than intended and may not recover.
How to stretch bamboo fabric back
- Soak the item in lukewarm water with a spoonful of hair conditioner for 20–30 minutes.
- Press out the water gently without wringing.
- Lay it flat on a towel and ease it back towards its original size, a little at a time and evenly.
- Let it dry flat, reshaping as it dries.
This recovers some length on knits such as T-shirts and pyjamas. Large shrinkage from hot drying is harder to reverse.
Worked example. A bamboo viscose nightdress 110 cm long, washed warm and tumble dried on high, can lose around 10 cm in length, in line with the 9% median for viscose in our records. The same nightdress washed at 30°C and hung to dry typically loses only a few centimetres in its first wash and then stays stable.
Should you size up in bamboo clothing?
For loose items such as pyjamas and lounge tops, your normal size usually works if you wash cool and dry flat. For close-fitting items such as leggings or fitted tees in 100% bamboo viscose, check the brand’s guidance; some allow for shrinkage in their sizing and others do not. If you know you will tumble dry, a little extra length is sensible.
Can you buy pre-shrunk bamboo fabric?
Some bamboo viscose garments are labelled pre-shrunk or are garment washed after sewing, which removes part of the shrinkage before you buy them. They still need gentle care, because viscose fibres keep swelling and relaxing in water. Check that the label says cool wash and low or no tumble drying, and expect a small change after the first wash even on pre-shrunk pieces.
Summary
- Most bamboo fabric is viscose, which shrinks more than any other common fibre.
- In our records viscose knit shrank a median 9% in length; cotton 6%, polyester 3%.
- The dryer causes the most shrinkage; cold washing and line drying the least.
- Bamboo-polyester and bamboo lyocell shrink less than 100% bamboo viscose.
- Wash cool, do not wring, and dry flat or low.
Questions
Does bamboo fabric shrink?
Yes. Most bamboo fabric is viscose, which shrinks more than cotton. Our viscose knit records show a median 9% length shrinkage.
Does bamboo shrink in the dryer?
Yes, the dryer causes the most shrinkage. Line dry, dry flat or tumble on low and remove while slightly damp.
Does bamboo shrink in cold water?
Only a little, mainly in the first wash as the knit relaxes. Cold washing and line drying keep it close to size.
Does bamboo shrink more than cotton?
Usually yes. In our records viscose knit shrank a median 9% in length and cotton 6%.
Can you unshrink bamboo fabric?
Partly. Soak it in lukewarm water with hair conditioner, press out the water, ease it back to size and dry it flat.
Textile engineer with 14+ years in dyeing and fabric development. He writes every guide on Dyeing Solution from real production work. Full profile