Mummy Sleeping Bag vs. Rectangular Sleeping Bag

Rectangular Sleeping Bag

One of the key pieces of gear you’ll be using on your overnights in the outdoors is a sleeping bag. This article was created to assist you in deciding what style of bag is best suited for your particular planned activity – whether you intend to sleep in a campground or deep in the backcountry.

There are two main sleeping bag shapes. A rectangular-shaped sleeping bag is a more traditional style, while a mummy-style sleeping bag is more form fitting and compact…it actually resembles an Egyptian mummy somewhat. Each type of sleeping bag shape has its own characteristics, strengths, and weaknesses, which we’ll explore in a little greater detail.

Sleeping Bag Comfort
Compared to rectangular sleeping bags, mummy bags, by design, offer less room inside which can result in some people feeling constricted. In addition, a person in a mummy bag must usually lie on his or her back for sleep. A rectangular bag, by contrast, offers more freedom of movement and a variety of sleeping positions.

Mummy Sleeping Bag

Sleeping Bag Warmth
A mummy bag is typically more efficient in very cold temperatures and, when they’re fully closed, only the mouth and nose of the sleeper are exposed. The form-fitting nature of a mummy bag increases its insulation qualities by reducing the amount of air around the body, so less heat has to be generated to maintain a constant temperature.

Most rectangular bags are best suited for temperatures above freezing, but there are some that are capable of keeping you warm in below zero temperatures. Rectangular sleeping bags that are rated for extreme temperatures tend to be pretty heavy and bulky which make them a good choice for tent and camper camping but not for backpackers.

Sleeping Bags and Backpacking
Mummy style sleeping bags are lighter and less bulky than comparably rated rectangular bags, making them ideal for backpacking and backcountry camping. Some lighter and smaller rectangular bags can be suitable for short-to medium-distance backpacking in moderate temperature climates. Remember, heat efficiency in rectangular sleeping bags is compromised, due to the more open, non-conforming cut.

Sleeping Bags and Car/Family Camping
Rectangular sleeping bags are ideally suited for car campers, where bag warmth, weight and size are not as high a priority as they would be while backpacking in the backcountry. Comfort is the highest priority, and rectangular sleeping bags, with their roomy design, shine for this purpose.

Sleeping Bag Prices
Cost often plays into the decision between a mummy bag versus a rectangular sleeping bag, for serious campers. The higher end, expensive, mummy bags can out price the priciest rectangular bags by several hundred dollars, while lower end mummy bags are often similarly priced to most rectangular bags. At the end of the day, let your use, frequency, personal preference, and pocketbook guide your selection.

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  • Steve

    It’s a complete embarrassment that y’all can write this post after discontinuing the Campmor branded rectangular down bags. I lost mine several years ago, and the replacement Kelty rect. down bags we got are $hit in comparison, only good for weekend car camping, hardly any down, even in the 15o model, and no zero-degree available like my old campmor baby that kept me cozy all over the mountains for 15 years. I mourn my loss.

  • Tiffany Akin

    Great comparison! As car campers, we definitely enjoy rectangular sleeping bags. In fact, I’ve really been wanting to try a double rectangular sleeping bag for me and my husband. It’s on my wish list:)

  • I am with Steve……..I would buy the Campmor Down rectangle bag. I owned two for ten years and traveled the Sierra’s, Boundary Waters, Philmont, etc. Bring back my favorite Bag.

  • Comanche Brave

    I have had at onetime nine different sleeping bags, along with two type of sleeping pads and a bivy bag. My -20 bag from REI is very cozy as long as it doesn’t get above -1.