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REI Co-op Magma 30 Sleeping Bag Review

Jenny Abegg author bio
ByJenny Abegg
Mar 12, 2025
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Our Take:
4.5/5
Editors' Pick
Certified

The REI Co-op Magma 30 ($349) is a fantastic option for weight-conscious backpackers on a budget, offering an impressive warmth-to-weight ratio at a mid-range price. Few other bags at this price point are as lightweight and packable, making the Magma 30 an excellent companion for long, demanding trips. It also comes in a wide range of sizes, accommodating various body types for a better overall fit. While you do sacrifice some features and comfort with its function-first design, the Magma 30 remains a strong choice for practical backpackers looking for performance at a great value.

Warmth / Weight

Warmth / Weight

4/5
Comfort

Comfort

4/5
Features

Features

3/5
Durability

Durability

3/5
Water Resistance

Water Resistance

3.5/5
Sustainability

Sustainability

4.9/5

Temp Rating

34/24°F (ISO Comfort/Limit)

Weight

1 lb. 8.4 oz.

Fill

12.7 oz. of 850-fill down

Shell

15D nylon

Shoulder/Hip Girth

62.5/54 in.

Packed Volume

7.5L

Other Temps

15F

Pros

Great price for an 850-fill-power-down bag.
A mind-boggling nine size options to choose from.
Internal phone pocket helps keep electronics warm and organized.

Cons

A bit bulky compared to other ultralight models, despite premium down.
Doesn’t quite nail its temp rating and sleeps cooler than expected.
The draft collar is awkward when the bag is unzipped.

For this season's top models, see our guide to the Best Backpacking Sleeping Bags.

For its price, the REI Co-op Magma 30 has a surprisingly good warmth-to-weight ratio, ranking it at the top of our list for value-seekers still aiming to minimize pack size and weight. It accomplishes this feat with 850-fill-power down—a lofty down we typically see in more premium sleeping bags—in addition to a thin 15-denier shell fabric and a trimmed-down feature set. These design points put the Magma 30 in the same playing field as more expensive bags like the Therm-a-Rest Parsec 20 ($470) and Sea to Summit Spark 15 ($549)—but for up to $200 less.


The best way to understand this is by looking closely at the numbers: The REI Co-op Magma 30 has a comfort rating of 34 degrees Fahrenheit and a limit rating of 24 degrees, while the Parsec 20 has a comfort rating of 29 and a lower limit of 18. To reach this temperature rating, the Magma 30 packs in 12.7 ounces of 850-fill-power down for a final weight of 1 pound 8.4 ounces. On the other hand, the Parsec is heavier at 1 pound 13 ounces but uses 1 pound 1 ounce of 900-fill-power down. Without getting too deep into the details, it’s safe to say that the bags are fairly close in warmth for weight, with the Magma perhaps slightly edging out the Parsec due to its loftier down.

Looking at the Nemo Riff 30 ($360) provides a better contrast: The Riff 30 isn’t quite as warm as the Magma 30, with a comfort rating of 39 and a lower limit of 29, yet it weighs over 5.5 ounces more at 1 pound 14 ounces. Right off the bat, you can see that it’s less efficient in terms of warmth-to-weight. Checking out the Riff’s fill weight confirms this: It only has 10 ounces of 800-fill-power down, compared to the Magma’s 12.7 ounces of 850-fill-power down. All told, the Magma 30 doesn’t offer the same level of thermal efficiency as heavy-hitters like the Feathered Friends Swallow UL or Sea to Summit Spark, but it’s not far behind and offers considerable savings, making it a suitable choice for all but the most militant ounce counters.


For my purposes—multi-day backpacking trips with a 55-liter backpacking pack that can handle up to about 35 pounds—I found the Magma 30’s weight and packed size to be perfectly sufficient. REI includes a stuff sack, but you’ll likely want to replace it with a compression sack to achieve a smaller packed size. And I can confirm that the Magma’s stated temperature rating is accurate: I’ve spent multiple nights in the backpacking sleeping bag in temperatures hovering just above freezing and felt on the edge of its comfort range. I wouldn’t want to push it into below-freezing temps.

The Magma scores above average for comfort and is a wonderfully cozy place to call home for the night for all but the most princess-in-the-pea sleepers. The bag features a silky 15-denier fabric along with an insulated yoke that hangs around the neck to fill in gaps of dead air space. Unfortunately, this yoke isn’t as foolproof or cozy as a draft collar and dangles awkwardly when the bag isn’t zipped up. I’d much prefer an integrated draft collar, which REI likely omitted for weight and cost savings.


I found the REI Co-op Magma 30 to strike a nice balance between roominess and weight savings, and the good news is that it’s offered in nine unisex sizes—so if you want a wider or longer silhouette, you can find one. The unique zipper path adds to the bag’s comfort, wrapping from the side to the front, which makes it easier to zip and unzip. Too often, I go to unzip my sleeping bag only to realize I’m lying on top of the zipper, but this happens far less often with the Magma’s thoughtful design.

REI kept features to a minimum with the Magma 30 to keep weight low. You get an insulated yoke at the neck instead of a draft collar, which helps minimize drafts but feels like an awkward afterthought in design. The bag also includes an interior stash pocket that fits a phone or headlamp, though its integrated flap makes it somewhat difficult to retrieve items in the middle of the night. Finally, the Magma’s zipper is very well executed: it’s a two-way design with a snag-free pull at the top—something I think every sleeping bag should have.

The Magma 30 falls on the more delicate end of the down sleeping bag spectrum given its thin 15-denier ripstop nylon shell. Thankfully, REI incorporated an anti-snag zipper pull to reduce catching when zipping and unzipping the bag. Durability isn’t a strong important factor in my sleeping bag decision-making, as I most often transition my sleeping bag straight from a stuff sack into a backpacking tent. That said, on cold mornings and evenings in Washington’s Enchantments, I wrapped myself in the Magma while making coffee or drinking tea, and the bag held up well to the exposure. Unless you’re particularly hard on your gear or frequently sleep en plein air (without a tent), the REI Co-op Magma 30 should have solid longevity.

A wet backpacking sleeping bag can turn an otherwise great backpacking trip into a miserable experience, especially if it's packing down insulation. Thankfully, the REI Co-op Magma 30 includes thoughtful design features to help mitigate moisture concerns. The Magma’s shell and lining are treated with a nonfluorinated durable water repellent (DWR) finish, allowing light moisture to bead up and roll off rather than soaking in. And if some dampness sneaks through, the bag’s water-resistant goose down provides an added layer of defense, which is important to helping the down maintain its loft and warmth. This level of water resistance is sufficient for dealing with light condensation or damp tent walls, but it should by no means be thought of as permission to get your bag wet. I recommend packing the Magma in a waterproof stuff sack and keeping it away from all moisture.

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Longevity

Choosing durable outdoor gear and keeping it in use for longer is one of the best ways to reduce environmental impact. Our proprietary longevity rating assesses factors like overall build quality, materials, fabric denier, component durability, and real-world performance. A green check indicates that we expect the product to be long-lasting relative to its peers, a yellow check mark indicates average longevity, and a red X indicates a product that may have a limited lifespan.

One of the key ways the REI Co-op Magma 30 differentiates itself from the rest of the market is its sizing. The bag has a traditional mummy shape and is available in nine different sizes, combining three lengths (short: 5’5”, medium: 5’11”, long: 6’5”) and three widths. I’m 5’6” and 135 pounds and tested the medium bag in its mid-range width. The fit felt notably tapered, especially around the hips and knees—for comparison, it measures 62.5 inches at the shoulders and 54 inches at the hips, whereas the Parsec has a slightly roomier 62- and 57-inch girth. That said, I’m always willing to accept a snugger fit for weight and space savings. If you prefer more room to toss and turn or sleep on your side, consider the wide versions.

Therm-a-Rest Parsec 20 ($470): A Level-Up
Despite the “20” in its name, the Therm-a-Rest Parsec 20 is a relatively close competitor to the Magma 30, with a comfort rating of 29 degrees compared to the Magma’s 34. The Parsec is about 4.5 ounces heavier and packs in over 4 ounces more down, with a slightly higher fill power (900 vs. 850). Where the Parsec really earns its higher price point is in its feature set and comfort: it offers a true draft collar (whereas the Magma’s yoke is underwhelming), an external pocket with a secure zipper, and a “Toe-asis” footbox that allows you to cozy up your feet on cold nights. Additionally, its slightly thicker 20-denier fabric feels noticeably softer and silkier. The Parsec’s overall dimensions are a bit roomier as well, though you can achieve a similar fit by opting for the wide-sized Magma. All told, the Parsec delivers a more premium feel and slightly more warmth than the Magma, but you’ll have to decide if that’s worth the additional investment.


Mountain Hardwear Bishop Pass 30 ($315): Solid Value & Durability
If the Magma 30’s price point is its most appealing trait, it’s worth looking at a cheaper sleeping bag like the Mountain Hardwear Bishop Pass 30. At this price point, some real compromises emerge in terms of warmth-to-weight. The Bishop Pass 30 isn’t as warm as the Magma 30, with a comfort rating of 40 degrees, and it’s about 4 ounces heavier overall at 1 pound 12.6 ounces. This is due to budget-minded choices such as a less-efficient 650-fill-power down and a thicker 30-denier shell. The Bishop Pass also lacks a draft collar or insulated yoke, though it does have a lofty baffle that frames the face to help trap warmth. If you’re looking to save, it’s a durable bag with decent comfort, but we don’t recommend it for those who prioritize keeping weight and bulk to a minimum. For more, read our Mountain Hardwear Bishop Pass 30 review.

REI Co-op Magma 30 ($349)
Staying warm in the REI Co-op Magma 30 Sleeping Bag in the tent
4.5/5

REI brings premium sleeping bag design to the masses with Magma, an 850-fill power model that boasts an extremely reasonable price point. Throw in a plethora of size options—the most of any model we’ve seen from a major brand—and there is a lot to like about this bag.

Temp Rating
34/24°F (ISO Comfort/Limit)
Weight
1 lb. 8.4 oz.
Fill
12.7 oz. of 850-fill down
Shell
15D nylon
Shoulder/Hip Girth
62.5/54 in.
Packed Volume
7.5L
Other Temps
15F
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Warmth / Weight

4/5
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Comfort

4/5
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Features

3/5
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Durability

3/5
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Water Resistance

3.5/5
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Sustainability

4.9/5
Therm-a-Rest Parsec 20 ($470)
Close-up of Therm-a-Rest Parsec 20 backpacking sleeping bag
4.5/5

A three-season bag that undercuts much of the competition on price, the Parsec offers a competitive warmth-to-weight ratio, above-average durability, and a handful of thoughtful quality-of-life features. Roomy dimensions and the lack of a short size make it a less ideal fit for smaller users.

Temp Rating
29/18˚F (ISO Comfort/Limit)
Weight
1 lb. 13 oz.
Fill
1 lb. 1 oz. of 900-fill down
Shell
20D nylon
Shoulder/Hip Girth
62/57 in.
Packed Volume
12L (8.8L compressed)
Other Temps
0F
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Warmth / Weight

4/5
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Comfort

4/5
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Features

4/5
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Durability

3.5/5
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Water Resistance

3.5/5
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Sustainability

2.6/5
Mountain Hardwear Bishop Pass 30 ($315)
Peaking out from the Mountain Hardwear Bishop Pass 30 Sleeping Bag
4.6/5

Despite its no-frills mummy design, there’s much to like about the reasonably priced Bishop Pass. It’s not supremely light or packable, but it’s a good value buy for hikers who sleep in relatively balmy three-season temps.

Temp Rating
40/30˚F (ISO Comfort/Limit)
Weight
1 lb. 12.6 oz.
Fill
12.3 oz. of 650-fill down
Shell
30D nylon
Shoulder/Hip Girth
62/53 in.
Packed Volume
7.8L
Other Temps
0, 15F
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Warmth / Weight

3/5
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Comfort

4/5
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Features

3/5
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Durability

4/5
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Water Resistance

2/5
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Sustainability

2.6/5

Is the Magma 30 for You?

The REI Co-op Magma 30 is an excellent choice for backpackers who prioritize a strong warmth-to-weight ratio at a reasonable price. With 850-fill-power down, a trimmed-down feature set, and a competitive weight, it performs alongside more premium options while maintaining a budget-friendly edge. It’s also offered in nine unisex sizes, so finding the right fit shouldn’t be an issue. However, the Magma lacks some comfort features found in modern sleeping bags—including a draft collar, venting, and a semi-rectangular shape—making it less ideal for picky sleepers or those needing a wider temperature range. But if you typically camp in above-freezing temperatures and want a lightweight, efficient sleeping bag, the Magma 30 is a high-value choice that punches above its price point.

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