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

Sleeping bags vary in packed size depending on insulation type, shell fabric, and lining. Because of this, you can’t choose a compression sack based solely on temperature rating — you’ll need to know the packed volume of your sleeping bag in litres.

How do I determine the volume of my sleeping bag?

If you have a Sea to Summit sleeping bag:
You can find the packed volume listed on the product page under Tech Specs.

If you have a sleeping bag from another brand:
Check the manufacturer's website for the dimensions or volume of the stuff sack that came with your bag. This volume represents the mildly compressed size of the sleeping bag.

If no volume is listed, and you have the stuff sack:

1. Measure the radius of the circular base and the height of the stuff sack in inches.

2. Use the formula: Volume = 3.2 × radius × radius × height

3. Divide the result by 61 to convert to litres

4. (Alternatively, measure in centimetres and divide the result 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 in inches.

3. Press the bag down until the top is roughly level (mild compression).

4. Measure the average depth of the bag in the box.

5. Multiply: length × width × depth = volume in cubic inches

6. Divide by 61 to convert to litres

7. (Alternatively, use centimetres and divide by 1000)

What now?

Once you know your sleeping bag’s volume in litres, refer to the Tech Specs section on our compression sack product pages to choose the right size.

Need help choosing the right style of compression sack?

Check out our blog post here:
Which Compression Sack Do I Need?

Explore the full range of compression sacks here: Compression Sacks