REI Magma 15 Review

I tested the REI Magma 15 sleeping bag and this is my verdict.

August 16, 2022
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The REI Magma 15 is one of the most affordable high-quality backpacking sleeping bags on the market. This down bag is very lightweight, has high fill power and does not break the bank. It could be roomier. But, for this price, we're not complaining.

Product Overview

REI Magma 15

Price: $399

rei magma 15

✅ Affordable

✅ Lightweight

✅ Warm

✅ Durable


❌ Not so spacious

❌ Bulky yoke

❌Limited fit for specific body types


  • Weight: 1 pound 12.2 ounces (28.2 ounces)
  • Fill: Goose down, water-resistant, Responsible Down Standard certified, and Bluesign approved
  • Fill Power: 850
  • Fill Weight: 15.9 ounces
  • Temperature Rating: Lower Limit: 16 degrees (F), “Tested Comfort”: 28 degrees (F)
  • Length: 72 inches
  • Shoulder Girth: 63 inches
  • Hip Measurements: 57 inches
  • Packed Size: 5.2 Liters, 8 inches x 14 inches by my measurement, circumference about 26 inches around

The REI Magma 15 sleeping bag offers major value for money. It is lightweight, durable and has high fill-power. It is the highest quality sleeping bag at this price point and one of the cheapest sleeping bags on the market.

The smooth anti-snag and versatile hybrid zipper system, plush but durable Pertex Quantum shell fabric, and highly insulated foot box and hood all come together to make an impressive sleeping bag for its weight.

For those who sleep mostly on their back and prefer a more fitted and confined sleeping environment, the Magma 15 mummy bag will be the versatile solution to your three-season nights in the outdoors.

However, for anyone who prefers a more spacious and open sleeping environment without the additional features of zippers, hoods, or a fully closed foot box, the Magma 15 may not be the best option and it would be worth considering other options.

To see how the other ultralight sleeping bags performed in our tests, read our post on the best ultralight sleeping bags.

Performance Test Results

rei magma 15 performance score graph

Weight: 8/10

At 28.2 ounces, The Magma 15 pushes the upper limit of what might be considered an ultralight sleeping bag with a limit of 16 degrees. The packed weight when compressed in the included compression sack is 1 lb 12.7 ounces (28.7 ounces), and out of the compression sack, it reads 1 lb 12.1 ounces (28.1 ounces).

rei magma 15
The REI Magma 15 weighs 28.8 ounces

When compared to stripped-down sleeping systems for a similar temperature rating, such as the Enlightened Equipment Enigma 20 degree (F) quilt that comes in at 21.2 ounces, you’re taking on an additional ⅓ of a pound. Yet, the Magma 15 is for a specific style of backcountry sleeper who may prefer the additional high-performing features for the minimal added weight.

With an exceptional zipper system, insulating hood and foot box, and thoughtful draft collar design, the Magma 15 becomes extremely versatile while still minimizing any added bulk and weight.

rei magma 15

Price: 10/10

The Magma 15 provides great value and performance for the listed price and is very affordable when comparing it to competing sleeping bags of similar specs. It performs excellently for a $400 sleeping bag.

rei magma 15
The REI Magma 15 is a $400 sleeping bag with quality, design, and features reasonable for its price.

The features that most notably attest to the price are the 16 oz of 850-fill power RDS certified goose down, the Bluesign-approved Pertex Quantum fabric encasing the down, and the full-length hybrid anti-snag YKK durable zipper system. While high performing, it wouldn’t be considered exceptional for the price in comparison to ultra-premium models.

rei magma 15

Compressibility: 7/10

When the Magma 15 is fully compressed, it’s included lightweight stuff-sack, it gets down to a volume of about 6 liters, with dimensions measuring 8” x 14”, and 26” around. While the bag may be compressed down closer to 5 liters with a heavy-duty compression sack strap system, the included stuff sack already seems to push the boundary of what would be appropriate long-term storage without damaging the insulation and loft long term.


The bag comes with a large mesh storage sack that you’ll want to store the bag in long term to preserve the loft and warmth of the insulation. Compared to other sleeping bags with similar warmth and features, it packs down comparably, and maybe even smaller than some.

It wouldn’t be considered bulky for the warmth and weight, but the additional features of the full-length zipper, hood, yoke, and full foot box certainly add some bulk compared to a standard sleeping bag or quilt rated at a similar temperature.

REI Magma 15's lightweight stuffsack

Warmth: 9/10

The Magma 15 is filled with 16 ounces of 850-fill Goose Down with a tested lower limit of 16 degrees (F), and tested comfort at 28 degrees (F). By itself, it is essentially a 3 season bag that might even be too warm in peak summer conditions.

temperature rating
Temperature Rating of REI Magma 15

The bag may perform well in moderate winter conditions with a heavy sleeping liner to extend the comfort range into 4 seasons, but that still might be pushing the limits of the bags’ ability. It is warm enough to use without a tent in conditions above 25 degrees for warm sleepers, and potentially above 35 degrees (F) for cold sleepers, with a sleeping pad underneath it. 

The REI Magma 15 is warmer than most other sleeping bags of a similar weight and style (hooded mummy) thanks to the 850-fill power and unique baffling system that maintains an even distribution of down.

rei magma 15

The bag is noticeably loftier than most bags and retains high volume when unpacked thanks to the baffle design. The bag features a lofted hood with a drawcord, a yoke/draft collar for the front of the neck, and a fitted foot box to offer maximum warmth and insulation. These features are absolutely worth the extra weight if you’ll be sleeping in temperatures under 30 degrees (F) and you need a versatile full coverage sleep system.


If you tend to sleep cold and sleep better in a slightly more limited and confined style of a bag (i.e. very tucked-in) these features will be worth the weight and cost.

temperature rating

Spaciousness: 5/10

The bag is a tapered/fitted mummy-style bag with a hood and fitted foot box. The regular men’s bag is 72” long, with a shoulder girth of 63” and a hip girth of 57”. The bag is not necessarily designed for individuals looking for a spacious sleeping system, but rather a fitted bag that compromises spaciousness for warmth and weight with all the features.

rei magma 15

For individuals under 6’ with a leaner/slimmer frame, the bag is just comfortably spacious enough to move one’s arms close to the body and change sleep positions in the bag. For individuals over 6’ and/or with wider frames the bag will feel cramped and limiting, restricting most range of motion when the bag is fully zipped to a mummy sleeping position.

rei magma 15

Individuals who tend to be side-sleepers, move often in their sleep, or don’t like feeling confined would most likely not find the bag spacious enough, especially if they are nearing the sizing dimensions. The tapered mummy style and fitted foot box limit movement compared to standard sleeping bags and quilts.

rei magma 15

The shape and spaciousness of the Magma 15 are well-suited to a specific kind of sleeper who prefers sleeping on their back and the feeling of being very “tucked-in”.

rei magma 15

Outer Shell Material: 10/10

One of the more high-performing and notable features of the Magma 15 is the outer shell fabric made of Pertex Quantum 15-denier ripstop nylon. While this material is not waterproof, it is impressively water resistant and breathable to manage condensation in average climate conditions with good airflow.

The outer shell is comparably durable, if not slightly more durable feeling than most other sleeping bags and systems of comparable warmth-to-weight ratio. The Magma 15 certainly does not compromise the performance and durability of its shell material.

rei magma 15
The REI Magma 15's outer shell is made up of Pertex Quantum 15-denier ripstop nylon

Comfort: 8/10

The feel and touch of the shell material are distinctively light, soft, and plush, compared to most other inner shell fabric materials that can feel plastic-like against bare skin. The warmth and spaciousness are very comfortable for those who sleep better in more fitted and confined conditions, while in temperatures between 20 and 30 degrees (F).

This bag is very comfortable considering its warmth and the liner material, but again, it's for a specific kind of sleeper; one who doesn’t move much in their sleep, prefers confined/being very tucked-in and is most comfortable sleeping on their back.


Versatility: 7/10

The Magma 15 is fairly versatile, thanks to the compromise of additional high-performing features for a little more weight. The full-length hybrid zip and hood contribute most to the versatility, making it possible to open up the bag at both ends and stick your legs and arms out or take on full coverage and insulation if needed.

The bag may be too warm for mid-summer conditions where nightly temperatures don’t fall below 50 degrees, while also not being warm enough for even moderate winter conditions below 20 degrees (F). The bag performs best in climates ranging from average shoulder seasons, and colder, potentially higher elevation, summer environments.

rei magma 15

Zippers: 10/10

The most impressive feature of the Magma 15 sleeping bag has to be the zipper system. It is definitely the easiest and smoothest zipper system I’ve ever used on a sleeping bag. It includes a full-length hybrid cross-body zipper with an internal anti-snag strip, a durable y-shaped plastic zipper cover, and a nicely sized zipper loop on the outside of the bag, with a lengthy and easy-to-find zipper tab on the inside of the bag.


The zipper cover and anti-snag strip make zipping and unzipping the bag very smooth, while the cross-body zipper design makes for a very natural and accessible zipping within the tapered, narrower style mummy bag. The hybrid zipper system allows you to open the bag from the inside and outside, and from the top and bottom simultaneously, making it one of the most versatile and easy-to-use zipper systems.


The zipper features a very durable and lightweight feeling plastic, while the actual zipper itself is the only feature made of lightweight metal. The only con may be the added bulk and weight of the zipper system, however, it is very high performing for the minimal weight that it adds.

The zippers are REI Magma 15's best features

Design & Features: 8/10

Hood: 8/10

The hood is not large enough to fit a pillow, it is very fitted and shaped to the sleeper's head, and can be dialed in with the two internal drawstrings. While the hood certainly adds weight to the bag, for those seeking a hooded sleeping bag system and slightly colder environments, the hood will undoubtedly be worth the weight and investment for how high-performing and insulative it is.

hood closure

Draft Collar: 9/10

The draft collar/yoke does make a significant difference in insulation, performing excellently for the weight and bulk it adds. With two additional internal drawstrings, it can also be a very versatile and secure fit. For those who tend to sleep warm, and in warmer conditions, the yoke/draft collar may not be worth the added weight and bulk, in addition to the irritation or potential awkwardness of their placement if those features are unfamiliar and new to the user.

rei magma 15

Foot Box: 8/10

The foot box is very well insulated and does an excellent job at keeping your feet warm. For individuals with feet above a size 11.5 in men’s or 13.5 in women’s, the foot box on the regular-sized Men’s bag may have your feet and toes feeling cramped and limited in space. At a size 12 men’s foot, I did feel that my toes were slightly cramped.


Considering the availability of a larger-sized bag for bodies nearing the upper limits of the regular bag dimensions that may help avoid any feelings of cramped toes, the foot box hits a great balance of warmth and insulation for a fitted/streamlined mummy-style foot box. When warm toes and feet are non-negotiable, the foot box on this bag ensures warmth, just enough space, and minimal added weight and bulk.

Other Features:

The bag comes with an ultralight stuff sack and a breathable mesh stack for long-term storage. The stuff sack is convenient for those who prefer the bag to be compressed at about 90% of its maximum to fit their organizational system, however, it is unnecessary for those who may already own a stuff sack or who prefer to simply stuff their sleeping bags/quilts directly into their backpacks.

The bag does not have any stash pockets.

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Ross Enlow photo

About Ross Enlow

Ross Enlow is an avid backpacker, trail runner, mountaineer, and gear enthusiast. He is a NOLS-certified Wilderness First Responder living in Portland, Oregon. 

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