Whether you’re setting off for a hike or planning to live out of your backpack for days on end, knowing how to fit a backpack is the key to comfort. When you’re at the trailhead looking at the ‘Hut – 7hrs’ DOC sign, you’ll want to know how to properly fit your hiking pack before you begin the journey. For more than 50 years, we’ve designed packs for all types of adventures, and we reckon we know what it takes to provide the support and fit you need.
You’re welcome to head into your local Macpac store for a free fitting, but you can also follow this blog to adjust your backpack to the best fit from home.
A Quick Fitting Guide
- Measure your torso length and choose the correct pack size.
- Position the hip belt over your iliac crest (hip bones).
- Tighten the shoulder straps so they contour around your shoulders.
- Adjust the sternum strap so it sits comfortably across your chest.
- Tighten the load lifters to roughly a 45° angle.
- Fine-tune all straps after walking for a few minutes with weight in the pack.
How to Measure Your Backpack Torso Length (And Choose The Right Size)
Start by locating your C7 vertebra. Tilt your head forward and feel down the back of your neck. It’s the prominent bony bump where your neck meets your upper back. There’s no need to press hard because you should feel it easily, it’s usually a bit higher than your shoulders.
Next, find your iliac crest. It’s the highest point on the top of your hip bone, and you can find it by gently pressing your waist with your thumb and forefinger.
Once you’ve located it, measure vertically from your C7 to the highest side point of your iliac crest to find your back length. This will give you your back measurement, which is the most important thing to know when choosing the right pack.
We do this because the harnesses of these packs are designed so that their loads are carried by your hips and legs. These muscles are far stronger than your upper back and shoulders. So, by getting your back length correct, you’ll have a pack that sits between the base of your spine and the bottom of your neck without any stress on your upper body.
How To Fit a Backpack (Step-by-Step Guide)
You’ve got your back measurement, and now it’s time to fit your backpack properly.
1. Loosen all the straps
We’re starting from scratch! Any time you fit a new pack (or re-fit an old favourite after a trip), you should start by loosening all the straps. Hip belt, shoulder straps, load lifters – reset it all.
2. Adjust the Back Length
Many hiking packs allow you to adjust the length of the back through sliders and straps, and now’s the time to have a go.
You can find the right size for you with our Pack Size Guide, but here's a quick cheat sheet:
Standard/Unisex
- S1: 39–46cm
- S2: 43–53cm
- S3: 50–60cm
Women's Specific
- W1: 37–44cm
- W2: 42–49cm
If you’re near the bottom of one range, and especially if you’re of light build, consider trying on the next size down. The opposite goes for anyone of a solid build. If you’re near the top of a size range — or you prefer to wear your hip belt lower — take a look at the next size up.
By loosening the webbing straps at the top of the internal compartment (AirFlo™ packs) or at the top of the harness on the back panel (Liberator™ harnesses) you can move the shoulder straps up or down to tailor the pack’s fit to your back length. This avoids a situation where your hip belt sits too high or too low.
Our harnesses are designed to carry the greatest loads — Liberator™, Liberator™ FreeLoad, and the AirFlo™ Flexi-Fit™ are all adjustable.
Pro Tip: Add weight to your pack after adjusting your back length, so you can fit it while simulated for real hike conditions. A sleeping bag, some clothes, or a couple of bags of flour should do the trick.
3. Tighten the Hip Belt
When it comes to comfort over long distances, your hip belt is your best friend. This is because you’re relying on your hips to carry most of the weight, giving your shoulders a break and managing fatigue.
To fit yours correctly, start by loosening all the straps a little, enough so that you can put the pack on and move the belt to hug the top of your iliac crest. The hip belt should cinch over your hip bones when you fasten the buckle, with the padding sitting comfortably. If the base of the pack is hanging below your hips, check your back length again and adjust the height of the shoulder straps if you’re having to cinch them tight.
4. Fit the Shoulder Straps
Next on the list are your shoulder straps, and what you’re looking for is a nice curve that follows the contour of your shoulder. Pull down on the straps so that you create a snug fit, but take care that the straps aren’t carrying much weight. Remember, it’s your hip belt that supports the bulk of the load.
5. Clip the Sternum Strap
The sternum strap sits across your chest, and its purpose is to keep your shoulders from feeling like they’re being pulled back. Where it sits is a matter of preference, but around 3cm below your collarbone is a great place to start.
There should be some tension to keep everything secure, but the strap shouldn't feel tight across your chest and your arms should be able to move freely.
6. Adjust the Load Lifters
The last straps to adjust are your load lifters. These straps pull the top of your pack towards your shoulders, helping to prevent you from feeling unbalanced.
Pull the loose ends down towards your chest to tighten them so that they angle back to the top of your pack at about 45°. Take care not to over tighten them and make sure there aren’t any gaps between the tops of your shoulders and the shoulder straps.
Pro Tip: Finding out you’ve got the wrong fit at home is a lot easier than finding out when you’re two hours into a three-day hike. Give it a go around the house for 20-30 minutes before you head out.
Common Backpack Fit Problems (and How to Fix Them)
Muscles fatigue over time, and as comfortable as they are, even the best harnesses require fine-tuning so you can keep going.
Here are a few of the most common problems we’ve come across:
- If you’re feeling a pinch on your hip bones, try adjusting the position of the hip belt. It does a lot of the work when it comes to supporting your pack, and sometimes adjusting the point of contact is all you need to do.
- If your chest/shoulders are feeling tight, loosening the sternum strap a touch.
- Shortening the back length and loosening the shoulder straps can adjust where the pack sits.
Fitting for Different Types of Backpacks
Fitting a Travel Backpack
The same principles apply when it comes to fitting a backpacking pack for travelling. However, when you’re heading off for potentially months on end it’s likely you’re going to carry (or try to carry) more than you’d take hiking. With this in mind, it’s even more important to get your hip belt dialled in from the start. It’ll make standing at airports and train stations easier, and your shoulders will love you for it after hours in transit. Here’s our range of travel backpacks.
Fitting an Everyday Backpack
Your daypack should be an uncomplicated setup, and if all it’s got is two shoulder straps then it’s purely a matter of preference. Some people like theirs higher, others lower. What’s important is that nothing’s pulling or swinging unnecessarily. If you’ve got a sternum strap on your backpack, its job is to ensure the other two straps aren’t sliding off the tops of your shoulders. If you’re looking for a daypack, you can explore our backpack range.
Backpack Fitting FAQs
How tight should a backpack hip belt be?
Your hip belt should feel secure without restricting movement or breathing. It should sit comfortably over your iliac crest (hip bones) and support most of the pack's weight. If it feels uncomfortable or creates pressure points, try adjusting its position slightly before tightening it again.
Why does my backpack hurt my shoulders?
Shoulder discomfort is often a sign that your backpack isn't fitted correctly. Your torso length may need adjusting, the hip belt could be sitting too low, or the shoulder straps may be carrying more weight than they should. Rechecking these adjustments will usually improve comfort.
Should a backpack sit on hips or shoulders?
For hiking and backpacking packs, most of the weight should sit on your hips rather than your shoulders. The hip belt is designed to support the bulk of the load, while the shoulder straps help stabilise the pack and keep it close to your body.
If you’re ever in doubt, feel free to visit your nearest Macpac store. Our team are more than happy to help you find the right pack and get it dialled for your next adventure. Until then, happy exploring!
