Will sweatpants shrink in the dryer?

Sweatpants are known for their comfort and relaxed fit, but what happens when you toss them in the dryer? Can they shrink and lose their shape?

Yes, sweatpants can shrink in the dryer, especially if they are made from 100% cotton¹ or fleece. High heat causes the fabric fibers to tighten, leading to noticeable shrinkage. Polyester and blended fabrics are more resistant but can still shrink if exposed to excessive heat.

Understanding how sweatpants shrink and how to prevent it can help you maintain their size and fit for longer. Let’s explore the causes and solutions.

What causes sweatpants to shrink in the dryer?

Shrinkage occurs when heat and moisture interact with fabric fibers.

The main reason sweatpants shrink in the dryer is that heat causes the fabric fibers to contract, especially natural fibers like cotton.

Factors That Contribute to Shrinkage:

✔ High heat – Hot air tightens fibers, reducing fabric size.
✔ Moisture absorption – Cotton and fleece absorb water, which alters their structure when dried.
✔ Tumble drying – The mechanical action of a dryer can accelerate shrinkage.
✔ Fabric composition – Natural fibers shrink more than synthetic ones.

If you want to avoid shrinkage, controlling heat and drying methods is key.

Which types of sweatpants shrink the most?

Not all sweatpants shrink equally—fabric type plays a big role.

Cotton and fleece sweatpants shrink the most, while polyester and synthetic blends are more resistant.

How Different Materials Shrink:

Fabric Type	Shrinkage Level	Reason
100% Cotton	High	Absorbs water and contracts with heat
Cotton-Fleece Blend	High	Fleece fibers tighten with heat exposure
Polyester	Low	Synthetic fibers resist shrinkage
Cotton-Polyester Blend	Moderate	Cotton shrinks, but polyester stabilizes it
Spandex Blend	Low	Stretchy fibers help retain shape

If you own 100% cotton sweatpants, expect significant shrinkage unless you take precautions.

How much do sweatpants shrink in the dryer?

The amount of shrinkage depends on the fabric and drying settings.

On average, 100% cotton sweatpants can shrink by 5–10% in length and width if dried on high heat. Polyester blends shrink less, around 2–5%.

Shrinkage Estimates by Material:

Fabric Type	Potential Shrinkage
100% Cotton	1-2 inches in length, 5-10% total size reduction
Fleece-Lined Cotton	5-10% size reduction
Cotton-Polyester Blend	2-5% shrinkage
100% Polyester	Minimal to no shrinkage

To minimize shrinkage, it’s best to air dry or use low heat.

How can you prevent sweatpants from shrinking?

To keep your sweatpants from shrinking, follow these care tips.

Avoid high heat and excessive drying time, and always check fabric care labels before washing and drying.

Best Ways to Prevent Shrinkage:

✔ Wash in cold water – Prevents fibers from contracting.
✔ Use a gentle wash cycle – Reduces agitation.
✔ Air dry or tumble dry on low heat – Prevents excessive heat damage.
✔ Turn sweatpants inside out before washing – Protects fabric integrity.

If shrinkage has already occurred, some methods can help stretch them back.

Can you unshrink sweatpants?

If your sweatpants have already shrunk, there are ways to try and restore their original size.

While you can’t completely reverse shrinkage, you can loosen the fibers using water and gentle stretching.

Steps to Unshrink Sweatpants:

1. Soak in lukewarm water – Add a small amount of hair conditioner or fabric softener.
2. Let sit for 15–30 minutes – Helps relax the fibers.
3. Gently stretch the fabric – Pull the legs and waistband while damp.
4. Air dry flat – Avoid the dryer to prevent re-shrinkage.

This method works best on cotton and cotton blends but may not be effective for polyester.

Are polyester sweatpants safe to put in the dryer?

Polyester is known for its durability, but is it safe for the dryer?

Yes, polyester sweatpants² can go in the dryer, but they should be dried on low heat to prevent damage.

Why Polyester Sweatpants Are Dryer-Safe:

✔ Resistant to shrinkage – Synthetic fibers hold their shape.
✔ Quick-drying – Less time needed in the dryer.
✔ Wrinkle-resistant – Low heat prevents fabric creasing.

However, high heat can cause polyester to lose elasticity over time.

How do you safely dry sweatpants without shrinking them?

To keep your sweatpants in their best condition, proper drying methods are essential.

Best Drying Methods:

✔ Air drying: Hang or lay flat to dry naturally.
✔ Low-heat tumble dry: Use a delicate setting to minimize shrinkage.
✔ Use dryer balls: Helps reduce drying time and heat exposure.
✔ Stretch while damp: Gently reshape before drying.

These techniques prevent unwanted shrinkage while maintaining fabric quality.

What are the best brands for shrink-resistant sweatpants?

Some brands use pre-shrunk or synthetic fabrics to prevent shrinking.

Best Sweatpant Brands for Minimal Shrinkage:

Brand	Features
Nike Tech Fleece	High-quality cotton-polyester blend
Lululemon City Sweat Jogger	Pre-shrunk, moisture-wicking fabric
Aritzia TNA Cozy Fleece	Durable fleece that holds shape
Champion Powerblend	Shrink-resistant cotton-poly blend
Under Armour Rival Fleece	Polyester-based, minimal shrinkage

Investing in high-quality sweatpants reduces the risk of shrinkage.

Can you intentionally shrink sweatpants?

If your sweatpants are too big, you might want to shrink them on purpose.

To shrink sweatpants, wash them in hot water and dry on high heat, but be aware that excessive shrinking can affect fit and comfort.

How to Shrink Sweatpants:

1. Wash in hot water – Helps tighten fabric fibers.
2. Tumble dry on high heat – Accelerates the shrinking process.
3. Repeat if necessary – Check the size after each cycle.

This method works best on cotton but may not be as effective on polyester blends.

Conclusion

Sweatpants can shrink in the dryer, especially if they are made from cotton or fleece. To prevent shrinkage³, wash in cold water, air dry, or use low heat. If they have already shrunk, soaking and stretching can help restore their fit. Polyester blends are more resistant to shrinking but should still be dried carefully. Choosing high-quality sweatpants can also reduce the risk of shrinkage and ensure long-lasting comfort.

---