Does Polyester Shrink? Barely, Even in the Dryer

Key Takeaways

• A 100% polyester shirt barely changes in a normal wash and dry; the mill set its size with far more heat.
• The heat to avoid is a cotton-setting iron, which can pass the mill's heat and shrink it.
• In a blend, the cotton or rayon share can shrink.
• Order polyester shirts in the size that fits now.

Polyester does not shrink much in a normal wash and tumble dry. The mill already shrank the fabric and set its size with heat, far hotter than a home dryer gets. So a 100% polyester shirt stays close to the size it arrives in. A blend with cotton or rayon is different, because those fibers can still shrink, and that changes how you size a group order.

Table of Contents

• Why Does Polyester Barely Shrink?
• Does Polyester Shrink in the Dryer?
• Does Polyester Shrink in the Wash or Hot Water?
• What Heat Can Shrink a Polyester Shirt?
• Does Polyester Shrink More Than Cotton?
• Which of Our T-Shirts Are All Polyester, and Which Are Blends?
• Should You Size Up Polyester Shirts?
• How Should Your Team Wash Polyester Shirts?
• Ordering Polyester Shirts for a Group
• Frequently Asked Questions
• Picking Polyester Shirts That Keep Their Size

Why Does Polyester Barely Shrink?

Polyester holds its size because the mill shrinks and sets the fabric with heat before it is cut and sewn. This step is called heat setting, and textile engineers at RWTH Aachen University describe it as necessary to keep a fabric's size accurate and stable.

In their 2016 heat-setting study, a single jersey polyester knit was set at 180 to 195°C (356 to 383°F). Single jersey is the plain knit of a lightweight tee. The knit shrank during that step, and it tended to shrink more as the heat rose or the time ran longer.

Water does little to polyester, since the fiber takes up almost none of it and a wash cannot swell it like cotton. Heat is what can change it: a polyester shirt holds close to its set size while laundry stays well below the heat that set it.

Does Polyester Shrink in the Dryer?

A normal or low tumble dry stays far below the heat that set a polyester knit, so a 100% polyester shirt barely changes. GINETEX, the association that owns the international care symbols, caps a normal tumble dry at 80°C (176°F) and a mild one at 60°C (140°F). Normal is the hottest tumble dry the symbols cover. A 2016 RWTH Aachen University study set its polyester knit at least 100°C (180°F) hotter.

Skip the high setting anyway: the makers of two of our performance tees name low as their limit. The A4 Cooling Performance T-Shirt's spec sheet says "Tumble Dry Low." Sport-Tek's sheet for its PosiCharge Competitor tee says to tumble dry low and remove promptly.

Under the FTC Care Labeling Rule, a label that says only "tumble dry" means a hot setting may be used regularly. A label that says "low" or "medium" names the setting to use, so pass that word on to whoever does the laundry.

When you browse custom t-shirts, you will find all-polyester, blend, and cotton fabrics, and the dryer question changes with each one.

Does Polyester Shrink in the Wash or Hot Water?

Polyester barely shrinks in the wash, even in hot water. The FTC Care Labeling Rule defines a "hot" wash as water at 112 to 145°F (45 to 63°C). It defines "cold" as water up to 86°F (30°C). The top of the hot range is more than 200°F below the lowest heat a 2016 RWTH Aachen study used to set its polyester knit.

A4's Cooling Performance sheet still reads "Machine Wash Cold," and the Sport-Tek PosiCharge Competitor sheet reads "Machine wash cold with like colors." Follow the label, because the maker wrote it for that fabric and its finish.

A polyester blend is different. Its cotton or rayon takes up water, so the wash and the dryer can shrink that part of the shirt.

What Heat Can Shrink a Polyester Shirt?

Heat near the mill's setting heat is what puts a polyester shirt's size at risk. In the RWTH Aachen study, the knit was set at 180 to 195°C (356 to 383°F). The household heat most likely to get there is an iron on the cotton setting, which GINETEX caps at 210°C (410°F). GINETEX lists polyester under the moderate setting, capped at 160°C (320°F).

A4 prints "Do Not Iron" on its Cooling Performance sheet, and Sport-Tek allows a "cool iron if necessary."

Does Polyester Shrink More Than Cotton?

No, cotton shrinks more than polyester, and for a different reason. Water swells cotton fibers, and the tumbling in a dryer brings most of the shrink out in the first few cycles. Our guide to how much cotton shrinks has the tested numbers in inches and what pre-shrunk means.

For a group that tumble dries everything and wants the fit to hold, 100% polyester is the safest pick.

Which of Our T-Shirts Are All Polyester, and Which Are Blends?

Our all-polyester t-shirts are performance tees, and our polyester blends include tri-blends and poly-cotton tees. The table lists 11 of them with the fiber from each maker's sheet, which tells you which shrink question applies.

The Sport-Tek PosiCharge Competitor T-Shirt, A4 Cooling Performance, and Team 365 Zone are polyester interlock, a smooth knit with the same face on both sides. The A4 and Nike rLegend tees use recycled polyester, which meets the same chemical definition of polyester in the FTC's fiber rule.

Among the blends, Next Level lists "fabric laundered" on its Tri-Blend and CVC sheets, meaning the fabric itself was washed before the shirt was sewn. Color can change a blend's mix, so check the fiber line for the color you order. Gildan's DryBlend is 65/35 polyester/cotton in Heather Dark Navy, Heather Deep Royal, and Heather Scarlet Red. The Bella + Canvas Black Heather Triblend is 70/15/15 cotton/polyester/rayon, so in that color it sizes like a cotton-heavy tee.

If the fiber choice is still open, compare polyester and cotton shirts on sweat, odor, and feel before you pick.

Should You Size Up Polyester Shirts?

No. A 100% polyester shirt barely changes after washing, so order the size that fits each person now. Sizing up for shrink only gives them a bigger shirt.

One of our performance tees runs fuller than the blend tees beside it. At size L, the Team 365 Zone Performance Long Sleeve T-Shirt measures 23 inches across the chest laid flat. The Bella + Canvas Tri-Blend, Gildan DryBlend, and Next Level CVC measure 22 inches, and the Next Level Tri-Blend measures 21 1/4. Fit names do not settle it, since Bella + Canvas's "retail fit" and Gildan's "classic fit" measure the same 22 inches.

Size each style from its own chart. Lay a shirt the person likes flat, measure across the chest an inch below the armpits and down the length, and pick the closest size. On the Team 365 Zone long sleeve, each size step adds 1 1/2 inches of chest and up to an inch of length. Charts carry a tolerance, too: a new all-polyester Paragon Bahama hooded long sleeve can measure 1/2 inch off its chart before any wash.

In an order that mixes fibers, size the cotton tees and the polyester tees separately. Someone who takes a larger cotton tee to allow for the dryer should take their true size in polyester. Blends sit between: a tri-blend, half polyester, sizes to fit now, while a cotton-heavy tee such as the Next Level CVC sizes like cotton.

How Should Your Team Wash Polyester Shirts?

Keeping a polyester shirt's size comes down to keeping its heat low. The A4 Cooling Performance and Sport-Tek PosiCharge Competitor sheets spell out nearly the same care. It fits in a note you can send with the shirts:

• Machine wash cold with like colors.
• Skip fabric softener; both makers say not to use it.
• Tumble dry low and take the shirts out promptly, or hang them to dry.
• Iron only if the label allows it, on the polyester or a cooler setting, never the cotton setting.

The same note works for blends, whose cotton and rayon are the parts a dryer can shrink. Hanging a blend shirt to dry keeps more of its length.

Ordering Polyester Shirts for a Group

The simplest fit check for a polyester group order is one real shirt. To check a finished custom piece, order one; there is no minimum. Have the person who wears that size try it on before you order the rest.

Custom orders that match your approved proof can't be returned or refunded. A one-piece order is refundable only for a defect or a proof mismatch.

Apparel ships in 1 to 2 weeks, and transit time is separate. Allow that time for the test shirt and again for the full order.

Have a question before you order? Contact us, and we'll get back to you within 24 hours on weekdays.

Frequently Asked Questions

Can you shrink a polyester shirt that is too big?

Not reliably. Home methods for shrinking polyester use the hottest wash and dryer, which stay far below the heat that set the fabric at the mill. An iron on the cotton setting runs past the setting GINETEX lists for polyester, so it is not a safe way to resize a shirt. Order the size that fits from the start.

Can you iron a polyester shirt?

Yes, at the setting its label names. The most to use is the moderate setting, which irons mark for polyester and wool and GINETEX caps at 160°C (320°F). Never use the cotton setting, up to 210°C (410°F). Sport-Tek's PosiCharge Competitor sheet asks for a cool iron, the lowest setting, and A4's Cooling Performance sheet says do not iron.

Does a tri-blend shirt shrink?

A tri-blend shirt shrinks a little, from its cotton and rayon half, while the polyester half holds its size. Bella + Canvas lists its Tri-Blend as pre-shrunk, and Next Level lists its Tri-Blend fabric as laundered. Size a tri-blend to fit now, and hang it to dry to keep more of its length.

Picking Polyester Shirts That Keep Their Size

Polyester barely shrinks in normal laundry, so the decisions that matter come before the order: the fiber, then the size. For a crew that tumble dries everything, a 100% polyester tee in the size that fits today keeps that fit. A tri-blend or cotton-heavy blend can lose a little to the dryer.

Browse the t-shirt collection for the fiber that suits the job, and send the care note with the shirts.