# What Can (and Can't) Go in the Tumble Dryer? A Fibre Guide > The tumble-dry symbol decides. Cotton and sturdy synthetics tumble at the heat the dots show; wool, silk, spandex and viscose belong on the airer. **Published :** 2026-06-08 --- **Summary:** Whether something can go in the tumble dryer comes down to two things: **what the tumble-dry symbol allows, and which fibre it is.** Cotton and sturdy synthetics tumble at the heat the dots show; **wool, silk, spandex and viscose belong on the airer** unless the label says otherwise. A crossed-out symbol means stop. There's no blanket yes-or-no: the decision is the symbol plus the fibre. On the four fibres that should air-dry — wool, silk, spandex and viscose — the default is the airing rack unless the label specifically permits a tumble. The tumble dryer ruins a lot of clothes by accident, because it adds the one thing many fibres can't take: heat. A wool jumper felts, a swimsuit goes baggy, a stretchy top never snaps back. None of that is bad luck — it's heat on the wrong fibre, and it's avoidable once you know which is which. > Before you close the door, answer two things. **First, what does the tumble-dry > symbol on the care label allow?** It is the binding instruction. **Second, which > fibre is it?** Some fibres are happy in the drum at the right heat; others should > be drying flat or hanging instead. The rest of this guide is those two questions, > answered fibre by fibre. ## Read the tumble-dry symbol first The tumble-dry symbol is a **circle inside a square**, and it is the binding instruction — it overrides any rule of thumb, including the fibre guidance below. It is one of the **ISO 3758** care symbols shown by GINETEX, which is why a crossed-out circle-in-a-square reliably means "do not tumble dry" rather than something you have to guess at. Three readings matter: **dry-tumble-low** **dry-tumble** **dry-tumble-no** A **crossed-out** circle-in-square means do not tumble dry — GINETEX defines it as "articles unsuitable for tumble drying", so stop there, whatever the fibre. If the symbol is *not* crossed out, the **dots set the heat ceiling**: one dot is a "mild drying process" with "reduced thermal action" (around **60 °C**), two dots is the "normal drying process… under normal load and temperature" (around **80 °C**), per GINETEX. The dots are about how much heat the drum applies, so they tell you the heat the garment is rated for — and if a garment carries no tumble symbol at all, the fibre chart below is your guide, with the four delicate fibres going to the airer. ## Why heat is the thing to watch The dryer adds heat, tumbling and time, and it's the **heat** that does the damage on the wrong fibre. On wool, the wool authority warns that heat, moisture and agitation can **felt** the fibre and make the shrinkage **effectively irreversible** (Woolmark) — which is why a felted jumper never comes back. On spandex and elastane, a textile scientist explains that heat **makes the fibres brittle and stretches the elastane**, so a hot dryer permanently robs leggings and swimwear of their snap-back (RMIT). Silk and viscose don't want the heat either: silk should be air-dried **away from high heat** (Woolite), and the viscose manufacturer's method is to **dry flat or hang** rather than machine dry (Asia Pacific Rayon). For the fibres that *can* go in the drum, the label's dots tell you the heat the garment is rated for — one dot for 60 °C, two for 80 °C (GINETEX) — while the four fibres above are better off skipping the dryer unless their own label specifically permits a tumble. ## The fibre-by-fibre tumble-dry chart Here is each fibre, with the textile authority behind the rule. The label's tumble symbol still has the final say on any individual garment. ## What you *can* tumble dry The everyday dryer load is **cotton and sturdy synthetics** — towels, T-shirts, sheets, polyester and nylon basics. These can usually go in the drum when the garment's tumble symbol allows it, **at the heat the dots show** (GINETEX). The routing is the label's, not a fixed rule by fibre: a two-dot symbol permits the normal 80 °C process, a one-dot symbol keeps it to the mild 60 °C process, and a crossed-out one rules the dryer out. Because the dots are a *ceiling* rather than an instruction to use maximum heat, the lower setting is the one to choose for anything lightweight, fitted or prone to shrinking (GINETEX). A set of wool dryer balls can go in the drum with these loads if you use them. When the dryer is the right call, the dots on the garment's own label are the only heat guide you need — match the cycle to them rather than to a fixed idea of what cotton or polyester "should" take. ## What to air-dry by default Four fibres should head for the airing rack rather than the drum unless their label specifically permits a tumble — and each has a textile authority behind the rule. - **Wool.** Dry it flat, not in the dryer. The wool authority's guidance is to dry flat unless the care label permits tumble drying, because **heat, moisture and agitation can felt wool and make the shrinkage effectively irreversible** (Woolmark) — and a tumble cycle supplies all three of those at once. Some superwash labels do allow a gentle tumble, so check the symbol; otherwise lay it flat. See [how to wash wool without shrinking](/blog/wash-wool-sweater-without-shrinking/index.md). - **Silk.** Air-dry it **away from high heat** (Woolite) rather than tumbling it. The same silk-care guidance pairs that with washing gently in cold water and not wringing, so the whole routine keeps silk off heat and rough handling. Our [silk guide](/blog/wash-silk-without-ruining-it/index.md) covers the rest. - **Spandex / elastane.** Keep it out of the hot dryer. A textile scientist (RMIT) explains that **heat makes the fibres brittle and stretches the elastane**, so the dryer permanently robs stretch garments of their snap-back; the scientist's finding came from swimwear. See [how to wash spandex](/blog/how-to-wash-spandex/index.md). - **Viscose / rayon.** The manufacturer's own method is to **dry flat or hang in a well-ventilated area** (Asia Pacific Rayon), so keep it out of the dryer unless the label allows it — the tumble dryer simply isn't part of the maker's drying routine. See [how to wash viscose](/blog/how-to-wash-viscose/index.md). None of these four belongs in the dryer by default. Wool's own authority says to **dry it flat** unless the label permits a tumble (Woolmark); silk should **air-dry away from high heat** (Woolite); viscose's maker says to **dry flat or hang in a well-ventilated area** (Asia Pacific Rayon); and spandex should **stay out of the dryer's heat**, which a textile scientist links to its lost stretch (RMIT). Air-drying takes longer than a tumble, but for these four fibres it is the supported default — wool flat, silk and viscose air-dried, spandex off the heat — and it costs nothing. ## Blends: follow the blend's own symbol Most clothes are a mix, and you don't have to do the fibre maths yourself: **a blend's care label already reflects the whole fibre mix**, so its tumble symbol is the binding instruction (GINETEX). Follow it — a wool or silk blend is governed by the blend's own symbol, not by the delicate fibre alone, and a mostly-cotton legging with a little elastane follows its symbol rather than the cotton. If the symbol allows a tumble, dry at the heat its dots show; if it's crossed out, air-dry. When the composition tag and a general rule of thumb seem to disagree, the label was set for the whole garment, so it's the instruction to trust over any single-fibre instinct. ## How to tumble dry without damage The whole decision collapses into a short routine. **Start with the tumble symbol.** A crossed-out circle-in-square means air-dry, full stop; if it isn't crossed out, the dots tell you the heat the garment is rated for — one dot around 60 °C, two dots around 80 °C (GINETEX). **Then check the fibre** against the chart: cotton and sturdy synthetics are the dryer's natural load, while wool, silk, spandex and viscose head for the airing rack unless the label says otherwise. **Set the heat to the dots** — they're a ceiling, not an instruction to use the maximum, so the lower setting suits anything lightweight, fitted or prone to shrinking. And when a garment is borderline — a wool blend, anything with stretch, a piece whose symbol you can't read — default to air-drying; you lose a little time and keep the garment. Run through that order and the dryer stops being the appliance that quietly wrecks the wrong fibres. ## Mistakes to avoid > **Warning:** > - **Don't tumble dry wool, silk, spandex or viscose by default.** Wool felts irreversibly (Woolmark), silk should air-dry away from heat (Woolite), the dryer permanently kills spandex's stretch (RMIT), and viscose's maker says dry flat or hang (APR). Tumble these only if the label's symbol specifically permits it. > - **Don't ignore a crossed-out tumble symbol.** It is binding and rules out the dryer whatever the fibre; this guide can't override it. > - **Don't reach for maximum heat because a fabric is 'dryer-safe'.** The dots are a ceiling, not a target (GINETEX), so use the lowest setting that dries the load — and drop to low for lightweight, fitted or shrink-prone pieces. ## The bottom line The tumble dryer isn't one decision, it's two: **what the tumble symbol allows, and which fibre you're holding.** Cotton and sturdy synthetics are the dryer's natural load, at the heat the dots show. Wool, silk, spandex and viscose default to the airing rack — each for a sourced reason, from felting to lost stretch — unless their label says otherwise. The four to remember are the ones the textile authorities single out — wool dried flat (Woolmark), silk and viscose air-dried (Woolite; Asia Pacific Rayon), and spandex kept off the heat (RMIT) — and for everything else, the dots on the label tell you the rest. Read the circle-in-a-square first, match the fibre second, set the heat to the dots, and you'll stop pulling felted, shrunken and baggy clothes out of the drum. ## Keep reading - [How to wash wool without shrinking](/blog/wash-wool-sweater-without-shrinking/index.md) — why wool felts, and how to dry it flat. - [How to wash silk without ruining it](/blog/wash-silk-without-ruining-it/index.md) — the delicate that air-dries away from heat. - [How to wash spandex](/blog/how-to-wash-spandex/index.md) — why the dryer's heat kills the stretch. - [How to wash viscose](/blog/how-to-wash-viscose/index.md) — the regenerated-cellulose fibre that wants the airing rack. - [What fabrics can you bleach?](/blog/what-fabrics-can-you-bleach/index.md) — the companion fibre-by-fibre safety chart for bleach.