How to Shrink Polyester – Step by Step

by Doug Berg | Last Updated: July 26, 2019

This Christmas my mother bought me a shirt as a gift and absolutely love it. Unfortunately, the shirt was just too big. I decided to try to shrink it and see if I could get it to fit better. I’ve had pretty good luck shrinking cotton in the past but this shirt was 100% polyester. I knew I didn’t have the skill sewing to shrink an article of clothing. Long story short, I ruined a shirt so you don’t have to. I wanted to share a few tips on shrinking polyester. Just don’t expect this process to shrink a polyester garment more than a half size.

Question: What’s different about polyester?

Unlike cotton or wool fabrics, polyester is a synthetic fabric. Instead of growing on a plant or animal, polyester is a kind of plastic. At low temperatures it’s strong and durable, and also resistant to staining because it doesn’t absorb moisture. But at high temperatures polyester can melt so the temperature range you need to maintain to shrink a garment but not melt it is pretty narrow. If you’re not careful you can even damage or ruin clothing just by drying.

First a warning – you can definitely ruin a garment this way. 

It can be tricky to keep the heat where you need it to be in a washer or dryer because they weren’t meant to be precisely controlled. Too hot and you will melt your garment, way too hot and you’ll get polyester residue all over your dryer. Try at your own risk! In addition to size, washing and drying in warm water will

Basics of Shrinking A Polyester Garment

We’re basically going to apply heat to cause the polyester fibers to become smaller. To do that we need to heat the garment to between 155-178?℉ (68-81℃). Avoid anything hotter than those temperatures or risk melting the synthetic material.

Question: How much will polyester shrink?

Expect a polyester garment to shrink between a quarter and a half of a size. It does depend on which of the methods you use. It will shrink at a much lower temperature than temperature than cotton. If you want to prevent shrinking then wash and rinse in cold water. You can then lay it out to dry. You can also dry clean polyester to prevent shrinking. When cleaning polyester in the laundry you can also wash by hand with a gentle detergent.

Steps to Shrink a Polyester Garment – (hot water wash method)

Does polyester shrink in hot water? Yes and it’s the basis for the first of our two methods to shrink polyester.

  1. To protect the colors and the outward appearance of your garment first turn it inside out. 
  2. Wash your garment alone in the washing machine. Set your water temperature to medium heat to high heat as it will go. Also, select the longest wash cycle you can. 
  3. As soon as the washer is finished, and before the garment can cool. Pull it directly from the hot water and throw into the dryer. Again, set the dryer for high heat and use the longest drying cycle allowed. 
  4. After drying, pull the garment out and lay flat. It will be very hot, so please be careful. Lay flat and allow to cool. 

If the temperature got high enough, the garment should be shrunk when you pull it out of the dryer. Drying is just as important as the hot water wash to get the maximum shrink. You can run it through the washing machine again if it shrank a little but it’s still too large. Be careful as repeated heat treatments will likely cause damage over time. You may notice faded colors, uneven shrinking or a loss of shape. Shrinking polyester in hot water and then drying is permanent

Alternate Method to Shrink Polyester

If you don’t have your own washer/dryer or you want a slower and more controllable process we have another method for you. You have to use heat but this time we’ll use a standard clothes iron to apply heat to the garments. 

How to use an Iron to Shrink Polyester

  1. Turn the garment inside out.
  2. Then, wash the garment in the washing machine using the hottest water and rinse setting allowed. 
  3. As soon as the wash cycle is complete, put the garment on an ironing board. Keep it inside out. 
  4. Cover the garment with a pressing cloth or towel. This keeps the heat from becoming too intense in any one area and also protects your iron. 
  5. IMPORTANT: Set your iron to the synthetic material heat setting, generally Low-Medium heat.
  6. Iron’s get plenty hot to melt polyester and if you don’t turn down the heat you can easily ruin your iron, garment, ironing board or all 3. 
  7. Iron the garment until dry. 

Let the garment cool and try it on. Shrinking polyester is a slow process. Take your time. You should have shrunk the garment by a small amount. Repeat if necessary but remember that repeating this process multiple times is likely to damage a garment.

Final Results

I hope this helped you to save a garment that would otherwise not be wearable. Polyester is a pretty forgiving material and you can certainly get it to shrink if you’re careful and don’t accidentally apply heat over the 155-178℉ temperatures I recommend. 

Unfortunately when I washed and dried my shirt it started to bunch up around the seams. When I was researching how to shrink polyester I knew it was possible to ruin a garment.

These two methods both work well and if you follow the process you shouldn’t have any problems. Glad I could share my experience, hope it turns out better for you.

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Doug has been an entrepreneur for years, starting several businesses. Doug is a web developer, father of 2 great kids and husband to the best wife ever. I've been working on building my custom tee shirt business for 3 years.