Sizing & Fitting a Backpack
A pack can make or break your trip (and back)
Because backpacking trips can be long and challenging, you want to make your experience is as comfortable and painless as possible. In order to have an enjoyable trip and keep your back happy, have a pack that fits you correctly and that is adjusted properly. Before purchasing a backpack, measure your body to find what size of pack is right for you. Once you’ve sized it properly, you can then fine-tune the adjustment (unless you have a fixed suspension) to fit your body perfectly.
Finding your Torso Length
Contrary to what you might think, finding the right backpack size has no relation to how tall you are. Rather the length of your torso is what’s important. Torso length is measured from your shoulders to the top of your hip bones. To find your exact measurement, have a friend help measure you following these steps:
- Locate your C7, or 7th cervical vertebra, by tilting your head forward. Have your friend feel along the base of your neck for a bony bump, the one that protrudes farthest from your spine. It is located where the slope of your shoulder meets your neck.
- Beginning at that spot, have your friend use a flexible tap measure to measure downward along your spine.
- Now you must find your iliac crest. Run your fingers down the sides of your rib cage until you reach the first hard spot, this is your hip bone. Place your hands on top with thumbs pointing behind you. This iliac crest serves as the “shelf” of your pelvic girdle.
- Draw an imaginary line between your thumbs to the point where they met in the middle. Have your friend measure to that point where it intersects with your spine, while still holding the top of the tape on your C7. Once you have finished measuring the distance from your C7 to your iliac crest, you now have your torso length.
- Compare this measurement to the information in the next section to find what backpack frame size is right for you.
Choosing the Correct Frame Size
As soon as you know the length of your torso, finding the right backpack frame size is easy. Although the sizes may differ slightly, use the following frame size guidelines unless otherwise stated by the manufacturer. Note, however, that each frame size can be adjusted to fit a slightly larger or smaller torso size.
- Extra Small: Up to 15-1/2 inches tall (up to 39 cm)
- Small: 16 – 17 1/2 inches tall (40 – 45 cm)
- Medium/Regular: 18 – 19 1/2 inches tall (46 – 50 cm)
- Large/Tall: 20 inches and up (51 cm and up)
Women-specific backpacks are also available, though less common. These packs have narrower shoulder yokes, conically shaped hip belts, and shorter torso lengths specifically designed to fit women. Men with narrow frames sometimes find these packs are a better fit for them as well.
Determining Hip Size
Some backpacks come with the option of interchangeable hip belts. In this case, it’s a good idea to know your hip size.
Wrap a flexible tape measure around the top of your hips, known as your “latitude line,” where you can feel your iliac crest. A properly fit hip belt should straddle your iliac crest, sitting about an inch above and below your “latitude line.” This measurement is your hip size.
- Small: 22 – 27 inch hip-line (56 – 69 cm)
- Medium: 28 – 34 inch hip-line (70 – 87 cm)
- Large: 35 – 39 inch hip-line (88 – 100 cm)
- Extra Large: 40 – 45 inch hip-line (101 – 114 cm)
How to Lift a Backpack
Properly lifting the pack onto your back will prevent back injuries – something you don’t want to incur before a backpacking or hiking trip. Before lifting your pack, take a wide stance and bend your knees slightly. Lift the pack onto a bent knee, and slide it onto one shoulder while swinging slowly around your body. Slide your other arm into the opposite strap. Fasten the hip belt and other straps to remove most of the weight from your shoulders.
Adjusting the Backpack
You now know how to fit and size a backpacking. However, it still may not be adjusted properly to your body. The following steps are used to adjust the backpack once it is packed and ready to hit the trail. You may want to practice this procedure prior to heading out in order to achieve the perfect fit.
Before you start, make sure all belts and straps are loosened. Remember, comfort isn’t just a luxury when backpacking. If your pack doesn’t fit correctly, it could result in injury.
Step 1: Hip belt
After you have lifted your pack onto your back using the instructions above, wrap the hip belt around your body so that the belt is cupping your hips. Clip the belt buckle on and tighten the straps evenly. However, you want to keep a 1 inch margin on both sides of the buckle. If it’s still too loose, you may want to try a different backpack or hip belt size. The goal is to have your hips hold 80%-90% of your backpack’s weight.
Step 2: Shoulder straps
Pull back and down on the shoulder straps to tighten them to fit close to your body and wrap around the shoulders. These shoulder straps are to simply hold the backpack against your body, not support its weight.
Step 3: Load lifters
Your pack’s load lifters are located just above your collarbones and attach the top of the pack to your shoulder straps. Gently pull these straps snug in order to take some weight off of your shoulders.
Step 4: Sternum strap
The sternum strap on your backpack, located on your chest, is simply meant to prevent your shoulder straps from slipping off, allowing your arms to move freely. Adjust this to a comfortable height across your chest that pulls the shoulder straps in.
Step 5: Stabilizer straps
If your pack has stabilizer straps, they are likely found on the bottom near the hip belt. Evenly pull the straps forward into your body in order to secure and stabilize your load. Your backpack should now be adjusted properly!
- Wild Backpacker – Backpack Buying Guide
- Wild Backpacker – How to Pack a Backpack
- YouTube – Fitting a Pack Comfortably Video with Wayne Gregory
- YouTube – How to Adjust a Hiking Backpack Video
- REI – Backpacks: Finding Your Torso and Hip Size
- REI – Backpacks: Adjusting the Fit