The better a sleeping bag fits, the warmer it will be. A properly fitting sleeping bag will wrap around you as snugly as possible, but not fit so tightly that it’s uncomfortable for you to sleep in. The basic idea is simple: You want to minimize the amount of air space around your body. This reduces the amount of air you have to heat up and keep warm, and limits the amount of warmth that gets pushed out when you shift around or roll over inside the bag.
There’s a tradeoff, however, in terms of comfort—which depends largely on your tolerance for being tightly confined inside a sleeping bag. Roomier bags make it easier to roll over and move around, a boon for restless sleepers. They also mitigate the sense of claustrophobia that tight-fitting sleeping bags often create. Roomier bags will be slightly less warm (for the reasons cited above), but a good night’s sleep is vastly more important than maximizing your bag’s warmth at the expense of quality shuteye.
Three Key Measurements to Consider
When it comes to fitting a sleeping bag, there are three important size dimensions to consider. In decreasing order of importance, they are: length, shoulder girth, and hip girth.
Length
First, length. Men’s sleeping bags come in two standard lengths, regular (which fits people up to 6 feet in height) and long (up to 6 feet 6 inches). A short version is sometimes available as well, which usually fits people up to 5 feet 6 inches. Women’s bags also come in a regular and long, though the measurements are different (usually up to 5 feet 4 inches and 5 feet 10 inches, respectively, though these measurements vary slightly by brand and style).
In general, you want to opt for the shortest length sleeping bag that fits you in order to minimize extra room (and maximize warmth) around your feet. (Opting for the shortest bag that fits also saves weight.) The key test is this: When you get inside the sleeping bag, and fully snug up the hood around your head, are your feet pushing against the end of the bag and thus compressing the insulation? If so, the bag is too short and will be less warm due to the insulation being compressed.
That being said, there are some advantages to having extra room below your feet, namely the ability to keep some clothes and/or footwear inside the bag with you to keep them warm. This is most useful on winter camping excursions, where you’ll want to keep your winter boot liners toasty overnight.
Shoulder Girth
Next in importance is shoulder girth, which is the circumference of the sleeping bag across the shoulders. Most men’s sleeping bags feature a shoulder girth somewhere between 60 inches and 64 inches (though some models can be as narrow as 58 inches or as wide as 66 inches). Four inches can make a surprising difference in the roominess of the bag. For most males of standard build, a 60-inch shoulder girth will feel on the snug side while a 64-inch bag will feel pleasantly roomy. Women’s sleeping bags are usually slightly narrower across the shoulders (shoulder girth generally ranges from 56 to 60 inches).
The easiest way to determine your preferred shoulder girth is to test drive several sleeping bags of different dimensions to hone in on the measurement that best balances comfort and warmth for you personally. Note that most ultralight bags tend toward the narrower end of the spectrum, which helps reduce the overall size (and weight) of the bag.
Hip Girth
Lastly, consider hip girth, the circumference of the sleeping bag across the hips. This dimension varies primarily based on whether it’s a men’s or women’s sleeping bag, but is generally consistent across the two gender styles. Most men’s bags feature a hip girth right around 58 inches, while women’s are often a bit wider (up to 60 inches) to better accommodate the slightly wider hips of the female physique. Again, the easiest way to zero in on your preferred hip girth is to try out several different models.
The Hood
The hood of a sleeping bag adds considerable warmth by trapping the heat would otherwise escape from your head. A properly fitting hood will wrap comfortably, and naturally, around your noggin. You shouldn’t feel like you have to cram your head into it to make it work. Once cinched up, it should move with your head as you roll from side-to-side.
So there you go. Sleep warm and comfortable out there!
LEARN MORE ABOUT SLEEPING BAGS FROM THESE RECENT POSTS
- Ultralight Winter Sleeping Bags (2011)
- One-Pound Sleeping Bags (2011)
- Snug up with the right sleep system for winter camping (2011)
- Gear Watch: Selk’bag Sleepwear System (2010)
- Gear Watch: Marmot Plasma Sleeping Bags (2010)
- Ultralight 15-Degree Sleeping Bags (2010)
- Sleeping Bag Warmth Update: European Norm rating s…(2009)
- How to Wash Your Sleeping Bag (2009)
- Drool List: Marmot Sleeping Bags (2009)
- Waterproof Goose Down? (2012)
- Synthetic Insulation: The Long and Short of It (2011)
- Down Time: The story of a miracle material (2011)
- The Incredible Structure of Goose Down (2011)
Equippedis an AMC Outdoors blog, written by Matt Heid.
FAQs
The basic idea is simple: You want to minimize the amount of air space around your body. This reduces the amount of air you have to heat up and keep warm, and limits the amount of warmth that gets pushed out when you shift around or roll over inside the bag.
How do you know what size sleeping bag to get? ›
Sizing your sleeping bag
The length of sleeping bag you need is based on your height, and it's important to not get one that's too short or too long. If your sleeping bag is too short, your feet and head will press against the ends of your bag, compressing the insulation there making it less effective.
What if sleeping bag is too big? ›
If your bag is too big in places, or too long, your body is going to have too much real estate to warm up. At the other end of the scale, a sleeping bag can be too small. The reason that sleeping bags are built with very slim shapes is that this is an easy way for a manufacturer to make a bag lighter.
Should I be touching the bottom of my sleeping bag with my feet? ›
Usually, it ends up being at least 6 inches extra bag, but having less space at the bottom is better since you stay warmer. Doesn't really matter, people are different heights so unless you are tall your feet normally don't go to the bottom of the bag.
Should a sleeping bag be tight? ›
You want your sleeping bag to be cosy, but not too tight. This will restrict its insulating power. And if you have a less body fat, think about getting a more insulating sleeping bag.
What are the 5 types of sleeping bags? ›
Below, we've listed five of the most common types of sleeping bags: rectangular, semi-rectangular, mummy, double and kid-sized.
How big should an adult sleeping bag be? ›
Our sleeping bag with feet for adults is available in three sizes: Small, S: length 160 cm, chest measurement 81 cm - 90 cm (Recommendation for a body size of 155-164cm) Medium, M: length 170 cm, chest measurement 91 cm - 98 cm (Recommendation for a body size of 165-174cm)
Are sleeping bags one size fits all? ›
Adult sleeping bags: Most bags come in regular and long sizes. Some also come in a short size. If your height is close to the upper end of a size's "fits up to" spec, try both that bag and the next size up to see which you prefer.
Is it better to roll or stuff a sleeping bag? ›
Here, however, it's fair to say: you can stuff it! This method is good for the material of both synthetic fibre and down sleeping bags. When a sleeping bag is rolled up, the fibres always get bent in the same places. This means the material loses thickness and insulation capacity.
Do you sleep with clothes on in a sleeping bag? ›
“We actually highly encourage people to have a sleeping bag that is either barely warm enough or not warm enough, then augment it with clothes inside the sleeping bag,” Hickner says, “under the idea that if it's cold enough that you're using a down sleeping bag, you probably have some warm jacket with you, so why not ...
The best way to handle this is to work the specific area by either gently massaging the down clusters or by lightly smacking and pushing the area. You also can put your sleep system in the dryer on the NO HEAT setting with a few tennis balls. Using tennis balls helps break up the down clusters and move the down around.
How should a sleeping bag fit? ›
Look for a length that fits your height as closely as possible without compressing any down in the footbox or hood. That close fit will ensure that you're not wasting energy warming empty air, helping your feet and head stay warm.
What if my bag is slightly too big? ›
Many airlines also have a sizer bin at the ticket counter, where you can make sure your bags are small enough to fit in the overhead bin of the aircraft before going through security. If your carry-on is too large – or too overstuffed – you might get stopped at the gate before boarding.
Is it OK if a sleep sack is too big? ›
An oversized sleep sack can pose a risk as it might ride up and cover your baby's face, impeding their ability to breathe. Conversely, a sack that's too small can restrict their natural movement and development.
How much room should be in a sleep sack? ›
Their arms should slide comfortably through the armholes without struggle, and there should be no excess fabric around the neck. The length of the sack should not exceed beyond their feet. There should be enough room for their little toes to dance in their sleep, but not so much that the extra fabric bunches up.
Should you sleep with less clothes in sleeping bag? ›
Keep the bag Warm not your clothes! Both clothes and sleeping bags are insulators, the problem with wearing too many clothes in your sleeping bag is that you will actually insulate yourself independent of the bag, as a result, your bag won't get warm or it will take a long time to warm up.
How do I know if my baby sleeping bag fits? ›
Just make sure it fits well around the shoulders so there's no risk of your baby's head slipping down into the bag. Sleeping bags are usually given a tog rating according to the warmth they provide – make sure your baby is in the right bag for the time of year.
Are you supposed to roll up a sleeping bag? ›
Rolling a sleeping bag efficiently not only conserves space but also protects the bag for future use.
