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REI Co-op Magma 15 Review

A premium quality sleeping bag at a tempting price
REI Co-op Magma 15
Credit: REI Co-op
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Price:  $399 List | $399.00 at REI
Pros:  Warm, lightweight, quality materials, packable
Cons:  A notch behind the best in terms of loft, comfort, and versatility
Manufacturer:   REI Co-op
By Jack Cramer  ⋅  Apr 30, 2021
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  • Warmth - 20% 8.0
  • Weight - 20% 7.0
  • Comfort - 20% 8.0
  • Packed Size - 15% 5.0
  • Versatility - 15% 7.0
  • Features & Design - 10% 6.0

Our Verdict

The REI Co-op Magma 15 promises premium performance at an awfully tempting price. In our tests, it displayed impressive warmth and respectable comfort in a compact and lightweight package. Its performance definitely approaches some of the top-scoring backpacking sleeping bags, but it doesn't quite match them. Our testers were particularly disappointed that its 850FP down didn't feel as lofty as the down in the best bags we've tried. Although the Magma 15 is still a good value, we think most shoppers will expect the best performance from a sleeping bag that costs this much. The Magma 15 can't quite it offer that, but it could be an awesome deal for a high-performance sleeping bag if you're able to find it on sale.

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REI Co-op Magma 15
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REI Co-op Magma 15
Awards  Editors' Choice Award Best Buy Award Best Buy Award 
Price $399 List
$399.00 at REI
$520.00 at Backcountry
Compare at 2 sellers
Check Price at Backcountry
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$100 List
$69.93 at REI
Overall Score Sort Icon
Bottom Line A premium quality sleeping bag at a tempting priceThe best ultra-premium bag that combines warmth, low weight, good packability, and luxurious comfortAn exceptional deal for a capable and sturdy backpacking sleeping bag for those looking to get outside without breaking the bankAn acceptable sleeping bag at a rock bottom price
Rating Categories REI Co-op Magma 15 Western Mountaineer... Mountain Hardwear B... REI Co-op Trailbrea...
Warmth (20%)
Weight (20%)
Comfort (20%)
Packed Size (15%)
Versatility (15%)
Features & Design (10%)
Specs REI Co-op Magma 15 Western Mountaineer... Mountain Hardwear B... REI Co-op Trailbrea...
Insulation 850 FP Goose Down, RDS-certified 850+ FP Down 650 FP Down Synthetic - Polyester
Compressed Volume 9.1 liters 7.2 liters 7.5 liters 9.8 liters
Measured Bag Weight (Size Long) 1.85 lbs. 1.62 lbs. 1.98 lbs. 2.74 lbs.
Manufacturer Claimed Weight (Size Regular) 1.76 lbs. 1.50 lbs. 1.79 lbs. 2.50 lbs.
Compression/Stuff Sack Weight 0.6 oz. 1.6 oz. 1.6 oz. 1.2 oz.
Hydrophobic Down Yes No No N/A
Manufacturer Temp Rating 15 F 30 F 30 F 30 F
EN Temp Rating (Lower Limit) 16 F Not rated 30 F 29 F
Fill Weight 15.9 oz. 13 oz. 15 oz. 21.1 oz.
Compression or Stuff Sack Included Stuff Stuff Stuff Stuff
Shell material Pertex (15D) Extremelite (12D) 20D Nylon Ripstop Polyester w/ DWR
DWR Treatment Yes No Yes No
Liner material 15D Nylon ripstop n/a 30D Plain weave nylon Polyester
Neck Baffle Yes No No No
Small Organization Pocket No No Yes Yes
Zipper Full-length / Left Side Full-length / Side 3/4-length / Left Side 3/4-Length / Left Side
Shoulder Girth 63 in. 64 in. 62 in. 62 in.
Hip Girth 57 in. Not stated 53 in. 56 in.
Foot Girth 37 in. 39 in. Not stated Not stated

Our Analysis and Test Results

According to our research, the Magma 15 is one of the most popular products on the REI website. In fact, it seems to be even more popular than the Magma 30. This perplexes us because we consider the 30F Magma to be more than warm enough for the most common outdoor applications. The 30 is also less expensive and weighs less. Both bags are great though. We would just steer people towards the lighter, more affordable 30-degree version unless they have concrete plans for cold shoulder-season overnights.

Performance Comparison

REI Co-op Magma 15 backpacking sleeping bag - the full-length zipper on the rei magma 15 makes it a little nicer...
The full-length zipper on the REI Magma 15 makes it a little nicer to use as a blanket on cold mornings.
Credit: Jack Cramer


The Magma 15 is filled with 15.9 oz of 850FP goose down. Although this down is certainly premium quality, it doesn't feel quite as lofty as the best down from Feathered Friends or Western Mountaineering. With its 850FP down, the Magma 15 receives a 16F lower limit EN temperature rating. This seems accurate to us compared to other EN ratings. Compared to Feathered Friends or Western Mountaineering bags though, the warmth seems to be on par with their 20F offerings.

REI Co-op Magma 15 backpacking sleeping bag - features like draft collars and zipper baffles can help ensure that...
Features like draft collars and zipper baffles can help ensure that your body heat stays trapped inside the sleeping bag, boosting the overall warmth.
Credit: Jack Cramer


We measured a size long at 1.85 lbs on our independent scale. That's impressively light for a bag that supplies this much warmth. The Magma 15 also comes with an ultralight stuff sack that weighs in under an ounce (0.6 oz). Together they're an excellent combination, but once again these numbers are just a little behind the top-performing backpacking sleeping bags.


The comfort of the Magma 15 is above average. The combination of high-quality down and 15-denier nylon creates a soft and cozy sleeping space. The 63-inch shoulder girth also felt ample in our tests. Some testers complained, however, about the narrow dimensions at the foot of the bag. They believe this made the bag feel uncomfortably restrictive so bigger folks or those that like to sprawl may want to consider a wider model.

REI Co-op Magma 15 backpacking sleeping bag - the 850fp down on the magma 15 is highly compressible, but the...
The 850FP down on the Magma 15 is highly compressible, but the simple stuff sack is not great at keeping it packed down.
Credit: Jack Cramer

Packed Size

One of the biggest benefits of down insulation is superior compressibility. The Magma 15 exemplifies this benefit. We were able to pack it down to 9.1 liters in a third-party compression sack. That's an outstanding size for a bag in this temp range. The included stuff sack, however, is not very effective at achieving full compression so you will need an after-market compression sack to fully enjoy this bag's minimal packed size.

REI Co-op Magma 15 backpacking sleeping bag - moisture is a huge problem for any down sleeping bag, including the...
Moisture is a huge problem for any down sleeping bag, including the Magma 15, because it causes the feathers to clump and compromises the warmth.
Credit: Jack Cramer


The Magma 15's versatility stacks up a little above average. Its full-length, two-way zipper is plenty long enough for venting excess on warm nights. This bag's down is contained inside horizontal baffles, but these baffles are unfortunately interrupted by a vertical stitch along the right side of the bag. That means that it's not possible to move insulation from the top to the bottom of the bag like you can with some ultra-premium bags that have truly continuous horizontal baffles. This reduces the Magma's usable temp range by a modest extent.

REI Co-op Magma 15 backpacking sleeping bag - the magma has a nice, sturdy two-way zipper with a y-shaped slide...
The Magma has a nice, sturdy two-way zipper with a Y-shaped slide that prevents snagging and allows you to vent around your feet while keeping the bag zipper up around your legs, hips, and torso.
Credit: Jack Cramer

Features & Design

This bag includes a basic, but well-executed, set of features. The Y-shaped zipper slide ensures that the sturdy stays smooth and snag-free. An internal organizational pocket offers a nice place to keep your small electronic devices warm and at hand. We also appreciate the sizeable neck baffle because it allowed our testers to really seal heat inside and provide a cozy surface to nestle into. Although the Magma 15 doesn't include very many more notable features, the ones that it does have feel more than adequate for most uses.

REI Co-op Magma 15 backpacking sleeping bag - the 15f temp rating is probably too warm for many summer trips, but...
The 15F temp rating is probably too warm for many summer trips, but it will probably be thoroughly appreciated if snow unexpectedly falls in autumn or spring.
Credit: Jack Cramer


The primary attraction of REI products is often their value. The Magma 15 is no exception. It offers excellent performance at a price that's a little less than the ultra-premium models. Still, the Magma 15 ain't cheap, and we think that if you're already committed to dropping serious cash on a sleeping bag, it's worth spending a little more to get the absolute best. Our testers believe the superior loft of the Feathered Friend and Western Mountaineering bags is well worth the higher cost. The Magma 15 is still worth considering, especially for REI members or when it goes on sale.


The REI-Coop Magma 15 comes close to matching the performance of the top-scoring backpacking sleeping bag, but it falls just short in a few ways. It boasts excellent warmth, weight, and comfort. However, its interrupted horizontal baffles diminish its versatility slightly and our testers think its 850FP down is a little less lofty than the best they've seen. We like this bag a lot, but not enough to recommend it over our favorite models from the small specialty manufacturers.

Jack Cramer

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