What size compression sack do I need for my sleeping bag?

Sleeping bags vary in packed volume depending on their insulation type and shell/liner fabrics. Because of this, you can’t simply match a temperature rating to a compression sack size. Instead, you’ll need to know your sleeping bag’s volume in liters and choose a compression sack accordingly.

If you own a Sea to Summit sleeping bag

Check the product page on our website – the packed volume is listed there.

If your bag is from another brand

Look for the volume of the supplied stuff sack:

• This is usually listed on the manufacturer’s website or a retailer page (e.g. REI).
• The quoted capacity equals the mildly compressed volume of your sleeping bag.

If no volume is quoted:

1. Measure the radius of the stuff sack’s circular base and its height (in inches).
2. Multiply: 3.2 × radius × radius × height.
3. Divide by 61 to convert to liters.
• If using centimeters: multiply, then divide by 1000.
  
  

If you don’t have the original stuff sack

1. Place the sleeping bag in a cardboard box that’s larger than the bag.
2. Measure the length and width of the box.
3. Press the bag down until the top surface is roughly level (mildly compressed).
4. Measure the average depth.
5. Multiply: length × width × depth = volume in cubic inches.
6. Divide by 61 (or by 1000 if measuring in cm) to get liters.
   
   

Next step

Now that you know your bag’s volume in liters, check the Tech Specs section of our compression sack pages to see which size will fit best!

For more guidance, see our blog post: Choosing the Right Compression Sack