Lighthouse Surrounded by Trail Trash

The Best Ultra Lightweight Sleeping Bags

Ultra lightweight sleeping bags are purpose-built for long-haul treks where space is at a premium and weight is counted in grams, but they can also be used on your ordinary family camping trips. I call that win-win!

The sleeping bag is part of “The Big Three:” your backpack, your tent, and your sleeping bag. These three items comprise the most weight, and take up the most space of all your gear. Also, they are items (aside from food and shoes) that can make–or break–your hike or tour. Be prepared to shell out good money up front (and not have to re-purchase something better later). This is an investment you’ll be putting to very good use. A sleeping bag is a camper’s best friend.


  1. Bag girth and length. You want enough room to be able to roll over in your bag but not so much that you are floating, or there is a lot of room at your toe. (Some bags do come in different lengths.) Air is insulating, but too much air will be drafty and cold. If you’re big or small, do take advantage of special bag sizes out there! Most bags come in varying sizes, and women’s versions with a wider hip.
  2. Synthetic vs. down. I would say most thru-hikers carry down bags, and are just careful to keep them dry. My bag gets damp occasionally, but dries quickly in the sun. Some ultra-light hikers carry handmade synthetic quilts and are very happy with them, but commercially-available synthetic bags are usually bulkier and heavier than down.
  3. Quilt vs. bag. Again, this is a personal preference, but if you’re not an experienced camper and the adventurous type, stick to a mummy bag with a floor and a hood.
  4. What temperature rating? This is another personal preference, but most people I have talked to are happy in the 15-25º range. It gets really cold in the desert at night! If I had to buy another bag today, it would be a 20º bag. My bag is too warm to sleep inside in Oregon in the summer, and since I cowboy camp, things get awkward.
  5. Does it have a continuous baffle? This feature allows you to shake down to the front/top of the bag if you’re too cold, or to the back/bottom if you’re too hot.
  6. Right or left zip? Seriously? Toss the dice!
  7. Down comes at a terrible price. Sure buy it, but make sure to speak up – you want to know where your down comes from! Encourage the brand to join the Cruelty-Free Down Challenge! Three, almost four, of the bags reviewed below are made with down from humanely-treated geese: ZPacks, Feathered Friends, Western Mountaineering, (and Marmot in the near future).
  8. Bottom line: your UL backpacking or bikepacking bag should definitely, definitely be under 2.5 pounds and should pack down to a bundle less than 14″ x 8″ x 8″ with ease.

Sleeping Bag Comparisons

These comparisons are for the men’s medium (~6 foot) lengths in a 15-20º range.

 ZPacks 20Marmot Helium 15Western Mountaineering UltraLite 20Feathered Friends Swallow UL 20Mountain Hardwear Phantom 15
FILL900 fill power down, Bluesign certified, not live-plucked850+ fill power goose down, will be RDS certified starting spring 2016Down, not force-fed or live-plucked900+ RDS certified goose down800-fill Q.Shield™ down

As you can see there are some USA-made bags out there that are really light and compressible, and cheaper than some of the big names. They’re also the only ones treating the source (geese) with respect. I tried to get the big players side-by-side here. I hope I’ve made it more of a no-brainer for you!

Hey, you: what is this table missing for warm down bags that are < 38oz (2lbs 6oz)?  


There is always the option to make your own gear (MYOG)! I like this option best. Unfortunately one of the best tutorials online about making your own sleeping quilt is not hosted anymore, but there is still evidence of it in the archive. It’s written by my pal Burrito Grande, a cool German 2013 thru-hiker. There is another tutorial available here, written in 1999.

Before my thru-hike I purchased an odd-size Mountain Hardwear sleeping bag and altered it. Since then I have sewn two MYOG quilts similar to the Enlightened Equipment quilts. These projects took me a few days of casual sewing, but quite a bit of planning. The second one was sewn at Hiker Heaven after having lost the first quilt in the Colorado River. It was really interesting to study the math behind down quilts. “MATH?” you ask? Yes, math. Down fill has different ratings, e.g. 700 fill power or 800 fillpower. This has to do with how many cubic inches each ounce of down will fill once expanded. For example, 800 fill power will fill 800 cubic inches per ounce. Quilt (or jacket, or bag) baffles have certain heights (0-4″, generally), and sleeping bags measurable volumes (width x length x baffle height), so you can then decide how many ounces of down to fill the bag with. Underfill the bag and you won’t have the temperature rating you expected. Overfill the bag, get unexpectedly low temperature rating results, and waste down. You do want to *slightly* overfill a bag to counteract the inevitability of down collapse due to wear, moisture, dirt, and oils, but people disagree on how much to initially overfill a bag (15-25%, usually). I would say don’t overfill by any more than that, and just wash your down bag frequently. People seem to think down has an expiration date on it, or that it goes bad. This simply is not true. Wash and care for your down, and it will take care of you a very long time. Washing a bag is a whole heck of a lot easier than opening it up and adding fresh feathers. Cute little geese were literally tortured for years for those feathers — treat ’em like gold.

Messing around with down fill amounts without understanding the mathematics behind it is a bit of a stab-in-the-dark, and potentially wasteful. Any guesses about how your DIY project is going to get “warmer,” without understanding how a short baffle can quickly be overfilled (to the point where there is no air space), and how baffle size and spacing matters, is a waste of time and money. Any talk about fill power without keeping in mind the volume of the item being filled, whether your down is actually the fill power advertised, and how much down was actually put in the item, is a waste of time and money. In other words, just because something says 950FP, does not mean it has enough down in it to be warm. The same two jackets (same construction) with the same amount of down, one is 800FP and one is 900FP… which do you buy? Trick question. Have I confused you yet?

So, when I say “quite a bit of planning,” I meant it. Typically nylons come in 55-60″ widths, including a selvage. That means your quilt is gonna be max 59″ wide with 1/2″ seam allowances. For some quilt makers, that’d be considered “wide,” and I like it wide. A lot of people will settle for 50″ but I cannot imagine doing that ever unless I was a petite woman. The Enlightened quilt was tapered at the leg, and I wanted that, too, so I started drawing out my “coffin” shape, then the baffle pattern I wanted. I wanted the zipper to come to the back of my knee, and I was going to use a sturdy plastic zipper, damn the extra weight I never wanted it to fail because of sand. Baffles would be made with very fine “noseeum” mesh.

Time for more math. How warm do you want your bag to be? What degreeº rating would you like it to have? That has to do with how tall your baffles are, and how thick your bag is when sitting with its natural day-to-day loft. Here’s a chart of what to expect:

Thickness (inch)Degree rating (ºF)
1″ (not baffled)50º

Both of my bags had between 2-3.5″ baffles meaning their loft, depending on how the bag was sitting, was anywhere between 2-3.5″ and more. They were in reality comfortable down to about 15-20º depending how clean they were. In our heads, we might imagine that baffles always stand perfectly upright and form little boxes inside our quilted item, but that is a fantasy. Some baffles might collapse in on other boxes, some boxes might be overfilled and rounded, some boxes might look like parallograms. It’s almost for the best when each baffle does its own thing in 3D space, and doesn’t sit like our fantasy would have it, because a vertical baffle is generally the most direct route of heat loss. Especially when we are using mesh (stretch) for baffles and not a woven fabric like nylon (non-stretch), we have to keep in mind our baffles are going to create unexpected shapes, especially when our bag is over-filled. This may or may not be helpful to the degree rating we expect our bag to have. Baffle design is a science, and can involve a ton of math.

You can purchase down at:

Ripstop by the Roll – 800FP

Loose Goose Down Supply – 900FP

My first bag was made using mostly recycled down from my Mountain Hardware 800FP bag, with just an ounce or two of purchased down.

For this sleeping bag I got my down from my first sleeping bag and a 800FP down vest. This is my old Mountain Hardware bag after being emptied (wet).

For my second bag, I bought my down from Feathered Friends. A little more expensive, but certified cruelty-free.

Purchase 7D down-proof nylon and mesh at:

I originally purchased black Ventum in 2016 at ZPacks but found WAY BETTER customer service at Ripstop By the Roll a couple years later. Beside, ZPacks stopped selling its fabric to the public. I found Ripstop’s nylons to be just as fine as the Ventum (though the Ventum is pretty darn nice).

Ripstop Nylon 6.6

0.5oz noseeum mesh

I basically cut my two sheets of nylon to size then used a fabric pencil (white color) to mark where my baffles would get sewn in, on the inside (wrong side) of the fabric. Having already cut noseeum mesh and sewn it into a very long spool of bias-cut 3.25″ strip, I then sewed the mesh to the fabric along the white lines, with a pittance of a seam allowance. I cut the baffle on a bias so that my bag would have more “give” were it to be tweaked top vs. bottom (rub your hands together to simulate what I’m talking about). I’m not sure I would do this again for my next quilt (next quilt?), because I’m not sure how much give it really needs on that plane. However, considering I sewed my current quilt in 2018 and have used it countless times since then without issue, it was probably a fine idea.

Now I have one half of the bag with a bunch of mesh sewn to it in a funny pattern (like the Enlightened baffle pattern, which seems wise to me). I sew the other half to it matching the baffle to its corresponding white line, working from the inside outward.

Here my quilt is with the baffles put in. The angle at the knee still hasn’t been cut because I wasn’t sure how much the nylon was going to fray. It didn’t.

I now have a quilt that just needs to be shut along the four edges.

Anyway, carrying on… Placing lower side edges right sides together, which is a little awkward but possible, I install the zipper at the bottom edges, continuing the seam up the side toward the head. I make sure to include tabs/snaps to shut the bag/hold it down:

For this project I hammered snaps onto 5/8″ grosgrain ribbon to make pulls for snaps. A little extra on the end makes them easier to grab. Nobody wants to feel stuck in bed.
The upper (hip, torso) portion of my bag has clips which I can attach to a band around my Thermarest, to make sure the bag stays snug around my body.

The sides are now closed. I encase and close the bottom with a draw cord and snap. My quilt is now a big bag and I can start filling it with bird feathers. Assuming my baffles would perpendicular to the plane of the floor when the bag was filled (which aha! tricked you, they’re not because I’m tricky and put my baffles at alternating angles to make ’em trapezoidal), now would be a good time to tally up the volume of each baffle. To measure how many ounces of feather to put in each baffle, I’d do something like:

width x length x baffle height (in inches) = baffle volume (cubic inches)


(baffle volume / fill power (cubic inches per ounce) ) * 1.2 = ounces of feathers required (with 20% overfill)

Math like this will totally help you decide how many ounces of goose down to buy when you MYOG. There is no need to guess. In a “sewn-through” flat baffle you would calculate the volume of a tube created by taking the flat baffle round. 1.25″ wide x 16″ long flat baffle (no height/loft)?

radius = 2.5 circumference / 2π (radius)
baffle volume = (π x radius2) x 16

baffle volume / fill power = ounces of feathers required (with 0 overfill)

Since the baffles will not all equal perfect tubes, you don’t really need to factor in an overfill here. The baffles on a sewn-through item will generally end up being a row of truncated circles — circles with two flat sides. This type of sewn-through flat baffle is easier to do than what I described above with the noseeum mesh, and would be common in puffy jackets and warm-weather quick quilts. I say warm weather because you won’t get much loft. You don’t need much loft in, though, if you have just the right amount of feathers and air space, and you keep the feathers clean and dry. ?

The foot box is completed, with zipper, snap, and stretchy drawcord.
I used heavier nylon for the head/foot casings because they will encounter more wear and tear.

Then I fill the bag (wet in this case), and finally I encase the top with a draw cord and snap, making sure to include my label.

But here you can see the shape, the baffle pattern, and how I put in the knee zip, arranged for pad clips, and drawstrings at the head and foot.
And I top it all off with my Little Package professional sewn-in woven label.

Bam. Donezo. I love the quilt and do not miss the sleeping bag. I might miss the sleeping bag hood, but actually no — I don’t. I love how I can shake the feathers down to the foot if nights will be warm, so my torso doesn’t overheat, and vice versa, shake feathers up to the torso for very cold nights. Essentially I move the feathers where I think I’ll need them, which other baffle designs won’t allow. I also love that I can also use this quilt in my Vanagon and anywhere else I might need extra warmth. Unfortunately this particular quilt (photographed) was lost to the hungry Colorado River. I immediately made my second after getting home. The successor to my beloved drowned “Fluffy McFluffin” was sewn from Ripstop by the Roll nylon in a really nice dark purple color, with a black underside, and looks/performs nearly identically.

Here are some ideas about how to move goose down from the bag you bought it in, to the bag you have sewn. For bags using fresh down, I disagree with Burrito Grande about getting the down wet to move it, because I want to be able to weigh out the amounts used in each baffle. I find that placing the small bag of down in a big garbage bag which has been tied as to only have an arm-sized opening, then reaching into that big bag to grab tight fistfuls of down, results in very little spill. Patience goes a very long way in having minimal spread of feathers! Afterward, I put some noseeum netting over a vacuum cleaner hose and clean up that way.

RDS stands for Responsible Down Standard. According to, “The Responsible Down Standard ensures that down and feathers come from ducks and geese that have been treated well. This means enabling them to live healthy lives, express innate behaviors, and not suffer from pain, fear or distress. The standard also follows the chain of custody from farm to product, so consumers can be confident that the down and feathers in the products they choose are truly RDS. The Responsible Down Standard is an independent, voluntary global standard, which means that companies can choose to certify their products to the RDS, even if there is no legislation requiring them to do so.”