Updated on October 7, 2020

While it is important to keep packability in mind when shopping for sleeping bags, comfort should always come first. The best rectangular sleeping bags are lightweight and compact, while providing enough moving space for you to avoid feeling trapped inside a cocoon.

Whether you are hiking long distances or setting off for a weekend of lakeside camping, a good night’s sleep is essential to keep you active and moving during the day. Rectangular sleeping bags tend to be slightly bulkier than their mummy-shaped counterparts, however they are ideal for those who enjoy some extra space during their sleep.

In this article, we’ll guide you through the five best rectangular sleeping bags available out on the market today, accounting for seasonality, price, and materials.

For more of our top backpacking gear recommendations, check out the Best Backpacking Sleeping Bags.


Quick Answer - The Best Rectangular Sleeping Bags

  1. Exped MegaSleep 40
  2. Exped MegaSleep 25
  3. REI Co-op Siesta 30
  4. Kelty Discovery 15


Comparison Table - Best Rectangular Sleeping Bag

PictureNameTemperature RatingWeightZipper LocationPriceRating
Exped MegaSleep 4040 Degrees (F)1 lb. 10.1 oz.Left/Right$$4.0
Exped MegaSleep 2525 Degrees (F)2 lbs. 6 oz.Left/Right$$$4.9
REI Co-op Siesta 3025 Degrees (F)4 lbs. 11 oz.Right$$4.1
Kelty Discovery 1515 Degrees (F)5 lbs. 8 oz.Right$$4.2
PictureNameTemperature RatingWeightZipper LocationPriceRating
Want to learn more about a technical term? Check out our Features Explained section below.

Need buying advice? Take a look at these Things to Consider.

Reviews - The Best Backpacking Rectangular Sleeping Bag

Exped MegaSleep 40

  • Fill: Polyester
  • Weight: 1 lb. 10.1 oz.
  • Temperature Rating: 40 Degrees (F)
  • Shell: 40-denier Ripstop Nylon
  • Insulation Type: Synthetic
  • Zipper Location: Left/Right
  • Lightweight Insulation, Highly Compressible
  • Draft Tube Along The Zipper Prevents Heat Loss
  • Includes A Storage Duffel For Fast Packing


It can be hard to think of a sleeping bag as an item that would be easy to travel with, as some of them can be quite bulky or hard to fold away once you’ve taken them out of their travel friendly packaging, but the Exped MegaSleep 40 sleeping bag defies all of those things, and more. The quick-drying microfiber insulation is made to keep you extremely warm and comfortable, whilst also ensuring the bag is lightweight and easy to compress down when you’re on the move.

The zipper is surrounded by a ‘draft tube’ which ensures that no warmth escapes and no cold air can get inside. The zipper is also able to be unzipped completely, allowing you to use the sleeping bag as a camping blanket without losing any warmth. The microfiber insulation is quick drying, which helps to ensure you’re ready to go in no time, even if your bag gets a little bit damp.

Exped MegaSleep 25

  • Fill: Polyester
  • Weight: 2 lbs. 6 oz.
  • Temperature Rating: 25 Degrees (F)
  • Shell: 40-denier Ripstop Nylon
  • Insulation Type: Synthetic
  • Zipper Location: Left/Right
  • Lightweight Microfiber Insulation
  • Fabric Is Tested For Harmful Substances
  • Long And Wide Shape For Maximum Comfort


If you’re in need of a sleeping bag that allows you to move around and get comfortable without losing any of the important warmth of the bag, the Exped MegaSleep 25 sleeping bag might just be the one for you. The soft and comfortable fabric is stretchy enough to move around in, allowing you to get a good night’s sleep even if you tend to be a bit more restless when you’re dreaming.

If you’re looking for even more room to move, you can purchase this bag and the Exped MegaSleep 40 bag, and zip them together to give you an ultrawide bag with a whole lot of room to move around in — pretty much like having the luxury of a double bed, but in a sleeping bag form. All the fabrics that are next-to-skin are treatment free, which is great for people who are more prone to getting itchy from fabrics they aren’t used to.

REI Co-op Siesta 30

  • Fill: Polyester Fibers
  • Weight: 4 lbs. 11 oz.
  • Temperature Rating: 25 Degrees (F)
  • Shell: Polyester Taffeta
  • Insulation Type: Synthetic
  • Zipper Location: Right
  • Quilt Construction Prevents Cold Spots And Stabilizes The Insulation
  • Left Side Zipper Lets You Fold Down The Top For A Bedlike Feel
  • Durable Water Repellent (DWR) Finish Repels Moisture And Stains


Even though a sleeping bag is expected to be a bit cramped and tight, to ensure maximum warmth potential is maintained, surely we can wish for a bag with a little bit of wiggle room too? Look no further than the REI Co-op Siesta 25 sleeping bag. This sleeping bag has enough components to meet any needs you may have, including a two-way main zipper, which allows you to unzip the bottom to let your feet have some air if it’s getting a bit too stuffy for your liking.

A shorter zipper on the other side of the bag allows you to fold down the top of the sleeping bag, giving you a bed-like feel. The polyester outside of the bag has been treated with a water resistant agent, so you don’t have to worry if your bag gets a bit damp on your camping trip.

Kelty Discovery 15

  • Fill: Cloudloft Synthetic Insulation
  • Weight: 5 lbs. 8 oz.
  • Temperature Rating: 15 Degrees (F)
  • Shell: 260-thread Polyester Pongee
  • Insulation Type: Synthetic
  • Zipper Location: Right
  • Top Collar Ensures Warmth Even In Low Temperatures
  • Built With Durable Materials
  • Dual-side Locking Zippers Allow The Top Panel To Flip Down


There are often times when you’re trekking up a mountain during the winter, and it starts to snow, where you start to realize that you should’ve invested in that sleeping bag that could actually handle the cold weather… like the Kelty Discovery.. This bag can keep you warm even when temperatures drop down to 15 degrees F.

The interior of the bag is lined with fleece, which gives you the factor of warmth and extreme comfort. The synthetic ‘cloud loft’ insulation combined with a collar at the top to protect from any draft ensures that you’ll be kept warm and cozy no matter the situation. This sleeping bag has been built to last, with tough construction that you can rely on, even on the top of a chilly mountain. Included in your purchase is a stuff sack, for easy portability.





The first thing to consider when buying a sleeping bag is in what conditions you will be using it in. The temperature rating of a sleeping bag will determine how comfortable you’ll be able to sleep in different temperatures, so it’s an important thing to consider before making your purchase.

Summer sleeping bags with a rating of 37°F and up provide the minimum amount of insulation for warmer climates. They are normally lightweight and easily packable, but not ideal in wet or cold environments.

Three-season sleeping bags with a rating between 20°F and 32°F are versatile and suited for traveling in spring and autumn as well as summer. This category of sleeping bags usually offers more features than simple summer bags, such as hoods and draft tubes to fight the cooler temperatures of the high mountains.

Winter sleeping bags have a rating of less than 20°F and are designed to protect you from the cold in the most frigid environments, including snow. Because of the added layer of insulation, they tend to be heavier and occupy more space in your backpack. However, if you plan to camp in alpine environments, they are an essential piece of equipment you can’t avoid taking with you.



Sleeping bags can be made with synthetic insulation or down insulation. The first category are usually cheaper and continue to offer protection against the cold even when wet, since synthetic fibers do not absorb water from either rain or moisture.

Down insulation is made from duck or goose feathers. On top of being lightweight and highly compressible, it offers more effective protection against the cold. The downside of down sleeping bags is that they do not absorb water and tend to cost more than those with synthetic fill.



If you are planning to hike for long distances with all your gear on your shoulders, the weight of the sleeping bag is something that should definitely be checked before buying. Ultra-lightweight sleeping bags are designed for thru-hiking and backpacking, however, the convenience of carrying a small amount of weight usually comes at a high price.

The weight of a sleeping bag often depends on the amount and type of insulating material. Down sleeping bags are lighter than synthetic bags, and summer sleeping bags are lighter than three-season and winter bags.



Another important characteristic to take into account when buying a sleeping bag is the amount of space it will occupy in your backpack. A lightweight sleeping bag isn’t necessarily also compressible, so make sure you know the volume of the bag when it is packed down. Volume is measured in liters. If you want to reduce bulk to a minimum, you should look for a sleeping bag that doesn’t occupy more than three liters of space.





A component of the sleeping bag that runs along with the zippers and is filled with insulating material, designed to prevent cold air from entering the bag while you are sleeping.


A water-repellent material.


The soft plumage of ducks or geese, used as the insulating material in sleeping bags to protect you against the cold.


Polyester fibers used in sleeping bags to insulate the interior against cold air. Synthetic materials do not absorb water and are usually cheaper than down.


The outer layer of a sleeping bag, normally built of water-repellent nylon.


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