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Best Ultralight Sleeping Bag? 7 Crowd Favorites

Best Ultralight Sleeping Bag? 7 Crowd Favorites

There’s truly nothing better than traipsing through the mountains on a long backpacking trip with a light pack in tow. However, ultralight gear that’s functional, durable, and compact is hard to find, especially when it comes to sleeping bags.

Thankfully, long gone are the days where lightweight sleeping bags were few and far between. Up next, I’ll introduce you to 7 of the best ultralight sleeping bags on the market today to help you find the right one for your upcoming adventures.

Without further ado, here are the top lightweight sleeping bags available, from lightest to heaviest, for you to check out.

NOTE: For ease of comparison, all quoted weights and prices are for the “regular” size of these sleeping bags. Most of these companies offer short, regular, and long sizes, which all vary in price and weight.


The 7 best ultralight sleeping bags from lightest to heaviest:

1. Sea to Summit Spark Ultralight 40 (12oz)

silver sleeping bag on white background

  • Weight: 12oz (340g)
  • Temperature Rating: 40ºF (5ºC)
  • Price: $319.00
  • Ideal Use: Ultralight summer backpacking

The lightest sleeping bag on our list at just 12oz (340g), the Sea to Summit Spark Ultralight 40 is a solid all-around option for ultralight backpacking in the summer months.

Due to its 40ºF (5ºC) temperature rating, this bag is best used in relatively warm climates. But, unlike many other ultralight models, the Spark offers plenty of interior wiggle room, a half-length zipper, and a hood for added comfort.

It’s made with 850+ fill Ultra-Dry Down that’s Responsible Down Standard (RDS) certified for sustainability. The shell is made with a super-thin 10D nylon fabric with a sewn-through construction to minimize cold spots.

One of the best parts about this sleeping bag is its impressively small packed size. It comes with its own compression bag, which packs down to just 1.5L for easy transport.


  • One of the lightest non-quilt options available
  • Super small packed size
  • Responsibly-sourced down
  • Dry-treated down


  • Warm weather use only

Learn more:


2. Feathered Friends Tanager 20 CFL (12.6oz)

green sleeping bag on white background

  • Weight: 12.6oz (357g)
  • Temperature Rating: 20ºF (-6.7ºC)
  • Price: $369.00
  • Ideal Use: Ultralight alpine trips where packability is essential

Boasting a truly impressive warmth-to-weight ratio, the Feathered Friends Tanager 20 CFL is rated to 20ºF (-6.7ºC), despite weighing just 12.6oz (357g).

To achieve these weight savings, Feathered Friends designed this bag with top-of-the-line 950 fill down and a 7D Pertex Quantum water-resistant fabric. They also eschewed a hood and zipper on this bag, giving it a draw-cord top instead.

In fact, the Tanager has a wide opening which is designed to be worn with a puffy jacket for maximum warmth. That way, you can make use of the gear you already have, while lightening your pack.

Plus, it packs down to a minuscule size, which is perfect for ultralight trips into chilly alpine areas.

Editor’s Note:

“After using this sleeping bag for years, I’m happy to say it’s one of the best pieces of gear I’ve ever owned. Lightweight, packable, and surprisingly warm, it pairs well with a down puffy and a warm hat for those chilly nights in the mountains.”


  • Great warmth-to-weight ratio
  • Water-resistant Pertex shell
  • Premium 950 fill down
  • Super small packed size


  • No hood
  • Some durability concerns with 7D fabric

Learn More:


3. Feathered Friends Vireo UL (15.5oz)

orange sleeping bag on white background

  • Weight: 15.5oz (441g)
  • Temperature Rating: 35ºF (1.7ºC)
  • Price: $329.00
  • Ideal Use: Ultralight summer trips and alpine climbing bivvies

Trailing right behind its slightly warmer cousin in weight, the Tanager, the Feathered Friends Vireo UL is an uber-packable option for those light and fast summer missions.

Perhaps the most unique part of this sleeping bag is its variable down fill. At the foot, this bag is rated to 25ºF (-4ºC), while the upper half is rated to 45ºF (7ºC).

This variable fill allows the Vireo to shed weight and keep you warm. It also has a wide top opening so it can be easily paired with a puffy down jacket for added warmth in the mountains.

Although the Vireo is slightly heavier than its warmer counterpart, it is made with a more durable 10D Pertex Endurance fabric. It also packs down to just about 1L, making it ideal for trips where packability is a must.

Editor’s Note:

“I’ve owned the Vireo UL for years and have used it on countless trips. It’s super packable, which makes it a great option for alpine climbing and as an emergency shelter in the winter. This bag also pairs amazingly well with a large puffy jacket fon chilly evenings, making it a close second in my mind to the Tanager CFL.”


  • Very packable
  • Variable insulation for weight and space savings
  • Premium 950 fill down
  • Water-resistant shell


  • Slightly heavier than some warmer alternatives

Learn more:


4. Western Mountaineering AstraLite (16oz)

teal sleeping bag on white background

  • Weight: 16oz (454g)
  • Temperature Rating: 26ºF (-3ºC)
  • Price: $420.00
  • Ideal Use: Thru-hiking trips weight savings are key

Offering a good mix of warmth, weight savings, and comfort, the Western Mountaineering AstraLite is a fan-favorite for thru-hikes. It features 850+ fill down with a 7D shell fabric to shed weight.

Although it’s technically a quilt, the AstraLite has a number of key features that make it more sleeping bag-esque. It boasts a fully insulated yoke with an elastic cord that helps to seal out the cold and trap in the heat as you sleep.

Underneath, the AstraLite has a number of elastic straps that help secure it to your sleeping pad so you don’t slide off at night. That way, it can offer just as much warmth as a standard sleeping bag without all the extra weight.


  • Insulated draft yoke for warmth
  • Elastic cords for securing to your sleeping pad
  • Packs down small


  • Down is not water-resistant

Learn More:


5. Zpacks 20F Classic (18.2oz)

blue sleeping bag on white background

  • Weight: 18.2 oz (517g)
  • Temperature Rating: 20ºF (-7ºC)
  • Price: $359.00
  • Ideal Use: Shoulder season trips and summertime alpine adventures

Designed to mix the benefits of a quilt with a sleeping bag, the Zpacks 20F Classic achieves a great blend of comfort and performance.

It’s made with DownTek water-resistant 900 fill down that’s responsibly-sourced. To help minimize the effects of wear-and-tear, each baffle in this sleeping bag is stuffed with 30% more down than is necessary to help extend the lifetime of the bag.

Additionally, the Zpacks 20F Classic has a 3/4 length zipper, which makes it easy to enter and exit throughout the night. This zipper also allows you to vent the sleeping bag for added airflow on warm nights.

Although it doesn’t come with a hood, this bag does have an elastic cord that can be cinched to minimize draft on cold nights. It’s also compatible with the company’s Goose Down Hood for added warmth.


  • Overstuffed with down for long-term performance
  • 3/4 length zipper for easy entry
  • DownTek water-resistant down


  • Slightly narrow construction

Learn more:


6. Therm-a-Rest Hyperion (20.5oz)

dark green sleeping bag on white background

  • Weight: 20.5oz (580g)
  • Temperature Rating: 20ºF (-6ºC)
  • Price: $409.95
  • Ideal Use: Extended backpacking trips in the mountains

Perhaps one of the lightest fully-featured sleeping bags that’s warm enough for three-season use, the Therm-a-Rest Hyperion is a solid option that can do it all.

Boasting 900 fill Nikwax Hydrophobic Down, this bag is water-resistant and highly packable, thanks to its 6″x8″ (15x20cm) stuff sack. All of this down is packed into a box baffle construction, which minimizes cold spots, even after frequent use.

Plus, the Hyperion comes with a hood and a 3/4 length zipper, which are two features that are hard to come by with ultralight sleeping bags. You can also connect the bag to your sleeping pad using the removable SynergyLink Connectors, which help stop you from sliding off your pad at night.


  • Comes with a hood
  • 3/4 length zipper
  • 900 fill water-resistant down for packability


  • Relatively expensive

Learn More:


7. Katabatic Gear Grenadier (28.8oz)

grey sleeping bag on white background

  • Weight: 28.8oz (816.4g)
  • Temperature Rating: 5ºF (-15ºC)
  • Price: $560.00
  • Ideal Use: Fast and light winter adventures

By summer sleeping bag standards, 28.9oz (816.4g) isn’t ultralight. But, when it comes to four-season bags that are suitable for winter use, the Katabatic Gear Grenadier is one of the warmest and lightest options available.

Featuring a Pertex Quantum shell for water-resistance and 900 fill HyperDry down that’s overstuffed in the foot area for added warmth, the Grenadier is an ultralight hiker’s best friend in the winter months.

It comes with a down-filled collar to seal out cold air as well as a trapezoidal foot box that’s designed for maximum comfort. Finally, the Grenadier comes with an integrated sleeping pad attachment system for added functionality as you snooze.


  • Designed for winter use
  • Down-filled collar to reduce draft
  • Overstuffed foot box for warmth


  • Expensive
  • No hood

Learn More:


How To Choose An Ultralight Sleeping Bag

Ultralight sleeping bags are particularly difficult to choose because it’s important to strike a good balance between weight savings and warmth. Here’s what you need to know to choose the best model for your needs.

What’s considered ‘ultralight’ for a sleeping Bag?

Ultralight can have a variety of definitions depending on who you ask. For three-season sleeping bags, anything under about 20oz (566g) would be considered ultralight by most backpackers.

Meanwhile, the keenest gram counters often argue that a summer bag should be under 16oz (453g) to qualify for the distinction of “ultralight.” For winter sleeping bags, anything under 32oz (907g) is pretty darn impressive in terms of weight.

Intended Use/Anticipated Conditions

Choosing an ultralight sleeping bag starts with understanding what you plan to use it for. As you can imagine, a model designed for summertime trips below treeline will be very different from one crafted for winter adventures.

The main concern here is the temperature rating. In general, it’s best to opt for a sleeping bag that’s 10º-15ºF (5.5-8.3ºC) warmer than the conditions you actually expect to face. That way, you can ensure that you get a good, comfortable night’s sleep, instead of shivering constantly until breakfast.

Hood vs. No Hood

One of the most obvious differences between the majority of ultralight sleeping bags and standard models is the fact that many ultralight options don’t have hoods.

Sleeping bag hoods are very popular among campers because they greatly increase your warmth at night without the need for a hat. However, they also greatly increase your pack weight, so they’re not as common on ultralight models.

If you do choose an ultralight sleeping bag with a hood, you may have to compromise a bit, either in terms of price or weight.

Alternatively, the no-hood option is ideal for anyone that already carries a warm hat (which is most hikers) or for campers that also plan to pack a big puffy jacket with a hood. If so, you can often save weight and money by going hood-free on your sleeping bag.

Water-Resistant Down vs. Regular Down

Many ultralight sleeping bags now come with water-resistant down, which is ideal for use in wet environments. Since down offers no insulating value when wet, these water-resistant options are helpful in situations where a bit of moisture is unavoidable. 

Of course, you’ll generally pay a premium for this high-quality down, but most backpackers find that it’s worth it for the peace of mind you get in the mountains.


Going hand-in-hand with a light weight is packability. For many ultralight hikers, compactness is just as important as weight savings, so finding a sleeping bag that packs down into a minuscule size is key.

Keep an eye out for models that come with ultralight compression sacks or that are made with 900+ fill down, which will be much more compact in transport.


One point of concern with ultralight gear is durability. The majority of sleeping bags in this review are made with shell fabrics that are 10D or thinner, which means they’re much more prone to rips and tears. 

Therefore, it’s critical that anyone buying an ultralight sleeping bag knows what they’re signing up for. Being gentle with these bags and bringing a set of repair patches on every trip is essential if you want to avoid spilling feathers all over your next campsite.


Up Next In Ultralight Backpacking:

Ultralight Bivy Sacks: How To Choose

49 Ways to Lighten Your Backpacking Load

Women’s Ultralight Backpacking Gear List: 9 lb Base Weight

Do You Need a Tent for Backpacking? (Pros/Cons and Alternatives)

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