If you're car camping, the bulk and weight of a sleeping bag are secondary concerns to comfort and warmth, but for backpackers, fastpackers and bikepackers, finding the best lightweight sleeping bag, which will still provide enough protection from the cold at night, is absolutely essential. The best lightweight sleeping bags for foot and bike-based adventurers also need to be a compact and packable.
Although there are light winter sleeping bags available, low-weight and reduced-bulk bags are usually designed for use in summer and the early part of the shoulder seasons – if you need extra warmth, it always comes with a weight penalty. Also, light weight tends to mean relatively expensive, with costs going up as weight goes down, so it’s a judgement call as to how much you value losing those few extra grams. That said, it works the other way too, so those super-bargain bags tend to be either very heavy or very cold. In other words, you get what you pay for.
We've covered a range of bags in this guide, in our quest to find the lightest sleeping bag, but should you decide that you can probably cope with a bit more weight in return for a cosy night's sleep, look instead at our best sleeping bag guide.
One gram-losing strategy to watch in some of the lightest sleeping bags on the market is shortening the zip, from full length down to a quarter or even smaller. This is popular with mountain marathon and adventure racer types, who run with the lightest, most compact sleeping bag they can get away with. However, for normal humans the shorter zip can lead to overheating on warmer evenings, and reduces the flexibility of the bag, not to mention making it tricky to get into, so one to consider carefully before taking the plunge.
Pair your purchase with one of the best camping mats for a great night's sleep out in the wilderness, and head to our best backpacking tent guide for similarly light and compact options. Hop to the bottom for some buying advice (including exactly what an EN rating is), or read on for our pick of the best lightweight sleeping bags to buy now.
The best lightweight sleeping bags 2022
The Rab Neutrino 400 Down Sleeping Bag will sound familiar to many an outdoorsy type, for the very good reason that Rab Neutrino down jackets and sleeping bags have been around for several decades. The S/S22 model does the heritage proud, weighing in at a decent lightweight 775g, with a comfort rating of -7C / 20F. In our Rab Neutrino 400 sleeping bag review, our tester found this the perfect companion for all sorts of chillier adventures where weight is a factor. The weight to warmth ratio is partly achieved by ingenious design trickery (chevron baffle design, trapezoidal boxwall construction), and solid quality filling – 800FP European Goose Down with Nikwax Fluorocarbon-Free Hydrophobic Finish. For an all-rounder bag that won't weigh you down but will handle cold reasonably well, this is a winner.
The best lightweight sleeping bag right now is the Rab Mythic Ultra 180. Rab has a lot of good history building excellent sleeping bags, and this flagship earns its leading slot due to being both highly technical, and really, really light. There are various weights in the range, so you can pick the best version for your lifestyle, but the lightest, the 180, clocks in at 400g. Yeah, 400 – less than four Mars bars. It's still limit rated to zero degrees too, which means it'll handle a wide range of outdoor excitement and still keep you happy.
Part of this achievement is down to top-notch materials, part to technical innovation. Rab has knocked up a world first – Thermo Ionic Lining Technology (TILT). This impressive-sounding acronym is actually a coating of Titanium bonded to the fibres, enabling them to reflect heat back at you, boosting warmth. It's a canny trick, and most importantly doesn't add much in the weight department.
If you're on a tight budget, check out the Decathlon Forclaz MT900. The folk at Decathlon have been busy here, knocking out a 700g mummy sleeping bag for a fraction of the price of the top performers in this class. There's a full length zip too, making this a very flexible late spring/summer/autumn bag indeed.
However, the temperature rating is where this falls down, considerably less warm than some of the competition. The key reason for that is the fill material, mixing in much cheaper duck feather to bring costs down, as well as a Polyamide Shell outer. Interesting to note the MT900 is a successor to the older Trek 900, but with a higher percentage of Duck Down, and all of it RDS certified - both considerable improvements. Price is still laughably low for this spec and weight too, making it an excellent contender for warmer camping. Overall: good design, good lightness, good price, budget fill materials – well worth a balanced look.
While we're not sold on the colour, the Robens Icefall Pro 300 offers some strong value for money in the lightweight sleeping bag arena, as well as being synthetic filled. This means it'll handle wet conditions much better than a down bag, still keeping you warm in soggier surroundings.
Designed for warmer weather camping only, this bag boasts plenty of handy design features, including a mummy shape and narrow foot box to keep heat trapped in around the legs, a generous length of 195cm, and a synthetic filling that effectively mimics the heating properties of down feathers. However, the standout is the central zip, which is intuitive and feels much easier to use than a traditional side positioning (one irritation is that the zip tends to catch on the surrounding fabric, so you'll need to be careful when opening and closing it). Head to our Robens Icefall Pro 300 sleeping bag review to find out more.
The Thermarest Hyperion 32UL boasts an enormous 900 fill GooseNikwax Hydrophobic Down to keep you warm down to a comfort limit of zero degrees, which is impressive considering how light this is. It also packs down to around the size of a 1L water bottle. The Nikwax treatment on the down itself staves off some of the worst effects of damp, with the treatment staying drier and, according to Nikwax, maintaining loft 60 times longer than untreated down.
A thermally-efficient box baffled construction and zoned fill (70% on the top and sides with 30% on the back) keeps the insulation around your core for maximum warmth and minimum weight, and finally the down filling is Responsible Down Standard Certified. It's not cheap, but it is one of the best lightweight sleeping bags you can buy, and after a long day carrying it, you won’t regret spending the pounds (or dollars) to save those grams.
The Rab Solar 2 Ultra is one of the heavier options listed here, but this well-priced mummy sleeping bag would still be a great choice if you need an option that'll keep you cosy in colder weather while still being nicely portable. Rated for three seasons (and capable of keeping out the cold around freezing point), it's brilliantly made with plenty of attention to detail and impressive eco-credentials.
Its 100% recycled polyester outer is combined with an inner triple layer of Recycled Stratus Synthetic Sheet Insulation, and it goes the extra distance in keeping you warm with Thermo Ionic Lining Technology, a metallic layer that reflects heat back into the bag more efficiently without adding too much to its weight. There's also an adjustable hood, a neck baffle to trap heat and a well-sized pocket for your phone, and the bag packs down really well thanks to its well-designed compression sack. Find out more in our Rab Solar Ultra 2 sleeping bag review.
The Sea to Summit Spark range includes a range of bags for all occasions, but we're going for the lightest available in the UK, the Sea to Summit Spark spl. That clocks in at a powerfully light 340g, quite astonishingly, in part due to the premium goose down, and a cunning design that boosts loft over the chest area with vertical baffles. That down has been dry treated too, widening the range of outdoor applications into adventure racing and the like. Even more impressively there's a half-length zip, something of a luxury when going this light.
The downside of all that lightness is a 9°c comfort rating, which is fairly warm for the UK, and really limits what you can get up to with this bag. However, that is the tradeoff, and for just a few grams (490 of them) you could get the Spark sp2 that'll cope with 4°c – the choice is yours...
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If you want to go exploring in the winter without filling your entire backpack with sleeping gear, the Vango Cobra 600 could be the sleeping bag for you. Our pick as the best lightweight sleeping bag for colder weather, the Cobra 600 is understandably a little weightier than many of the other options in this list, but it packs an impressive amount of warmth in a relatively compact package. A 20D 380T Nylon outer shell feels durable and is water-resistant, while an aluminimised layer works effectively to reflect your own body heat back to you and boost warmth further. The stuffing – ethically sourced goose down – has also been treated for water-resistance. Vango has shaped the bag to keep the heat in too; so it's fitted ergonomically around the head and shoulders, while the seams are found in the lower section. In our Vango Cobra sleeping bag review, our tester was also impressed with the zip – the full-length, two way zip has a clever anti-catch design. There's an internal pocket for stashing valuables, too.
If your budget is tight check out the Alpkit PipeDream 200. While the higher temperature rating means this one is strictly for summer-weather trips, it offers a strong warmth-to-weight ratio for a very reasonable price. A filling of water-resistant animal down traps in heat quickly, and the bag packs down to the size of a small loaf of bread for easy transportation. While it's nice and soft against the skin, this is a barely-there bag, so don't expect snuggliness. In our Alpkit PipeDream 200 review, our tester found it tipped the scales lighter than stated (485g rather than 545g), and also that it was on the shorter side.
Whether you take into account the budget price tag or you don't, the Vango Ultralite Pro 100 is an impressive sleeping bag. The Thermal Reverb system of reflective aluminised lining is designed to bounce your own body heat back to you, and the Polair Active outer fabric remains soft and warm to the touch. At 900g it’s not feather-lite, but it’s still compact and comfortable to carry when backpacking and hiking. Better still, it comes recommended by both the DofE and The Scout Association, and has an extremely reasonable price tag too.
The Mountain Hardwear Lamina line is packed with light-for-their-warmth synthetic bags, and this is the lightest in the family. Coming in just under a kilo, it’s heavier than some but also very robust. A 30D Nylon Ripstop shell will last years, and the Thermal.Q artificial down insulation will keep you toasty in all weathers down to minus one degrees – an ideal combination for UK adventures. Although the comfort rating stops at a chilly three degrees, Mountain Hardwear has set the ‘comfort limit’ at minus three, which is really plumbing the mercury for such a light bag. This is partly achieved through thermal mapping, which allocates the heaviest insulation to where it is most needed, around your core. In addition, the ingenious design of the Lamina line all adds up to a bag that punches well above its weight, such as the draft collar, tailored hood and anti-snag zip.
The Mountain Equipment Helium 250 is a lovely bag for summer adventures, and the build quality will last for ages too. Weighing in well under a kilo it’s no heavyweight, but the 254g of 90-10 Pure Duck Down fill will take some looking after to deliver the full insulation rating of a comfort rating of 8°C, with a limit at 3°C (extreme is a scary -11°C, which is very unlikely in summer).
As you’d expect from Mountain Equipment, the Helium spec list reads well, even though it’s not the lightest down bag here. An Alpine cut keeps heat trapped, and Slanted Box-Wall baffles should keep the down well distributed and lofted. Elsewhere there's an anatomically shaped hood and anatomically shaped foot-box, plus a heat-retaining internal collar. The included waterproof roll-top stuff-sack will help protect your down bag if exposed to the elements.
How to choose the best lightweight sleeping bag
There are a few things to know before you make your purchase. Sleeping bags usually state an EN rating, which is the European standard EN13537. EN13537 uses a thermal manikin test that produces four temperature results: upper limit, comfort, lower limit/transition, and extreme. Of these four ratings, ’comfort’ and ’lower limit/transition’ are the most helpful and are what most people look at when buying a sleeping bag. It's also worth bearing in mind that the 'extreme' ratings are exactly that - they're right on the edge where the bag stops working and you go into hypothermia - not a fun place to be.
If you get colder faster than the average person, look at sleeping bags with a higher lower limit. Remember too that real-world variables can have an impact on the performance of a sleeping bag, so these ranges are just a guideline.
Even in the summer heat temperatures can drop at night, and even more so as you climb above sea level (approximately 1 degree less for every 100m), so single-figure EN ratings are a good choice even for a light UK summer sleeping bag.
Unfortunately, while technological advancements mean that most hardware is getting lighter and lighter, there are still limits to what you can do, and nowhere more acute than in sleeping bags. Lighter materials shave off those grams, but lose lots of durability. Elsewhere, DWR coatings and treatments might add vital damp-proofing, but also add in a few grams themselves – there's literally no escape from the scales.
Down filling offers the lightest and warmest potential, but is pretty useless in damp conditions, while artificial fibres tend to be heavier and bulkier, but much happier in soggy UK conditions.
How we test the best lightweight sleeping bags
To put together this ranking, wherever possible we call the lightweight sleeping bag in and test it out overnight to see how it performs. We'll look at how effectively it keeps us warm, but also how functional it is as a design – is it ergonomically shaped? Can we get in and out of it easily, and does it pack up without too much hassle? Are there any extra design features, like tech pockets, worth considering? Does it feel well made and robust?
Because this particular guide is all about small and light bags, we'll look at the specs for the bag, how much it weighs compared to its packed size, and how that matches up against competitors' efforts. Here, we'll also factor in how much it costs before deciding where the bag should sit in the ranking.
Info from the brand around how the sleeping bag has been produced and any notable technologies also feed into our decision making, along with our knowledge about the brand, its reputation, and our experience with its products so far. Finally, we look at what other reviewers have said, to make sure we're not missing anything big.
In the cases where we haven't been able to get hold of a sleeping bag, but feel it's worthy of inclusion, we research what other customers and reviewers have said, and combine that with our knowledge of the market to put together an informed blurb for you to base your decision off. Find out more about how we test at T3 here.