The Complete Guide to Backpacks and Rucksacks — Carrying Everything You Need, Comfortably

Why Fit Matters More Than Features

A perfectly fitted basic backpack will outperform a poorly fitted pack loaded with premium features on every trip, every time. This is not opinion — it is a biomechanical reality. When a pack fits correctly, the weight transfers efficiently from the pack through the hip belt to your skeleton. When it does not fit, that weight shifts to your shoulders, your lower back compensates, and fatigue, pain, and potential injury follow.

The most important specification of any backpack is not its weight, its number of pockets, or its brand reputation. It is whether the pack matches your torso length and transfers weight to your hips. Everything else is secondary.

Capacity — How Many Litres Do You Actually Need?

Backpack capacity is measured in litres and indicates the total internal volume of the pack, including all pockets and compartments. Choosing the right capacity means matching the pack to your trip length, your gear bulk, and the season.

10–20 litres — Suitable for short day hikes and trail running. Holds water, snacks, a lightweight jacket, and a few essentials. Compact and close-fitting.

20–35 litres — The standard day pack range. Sufficient for a full day on the trail including lunch, extra layers, first aid, and navigation equipment. Also suitable for ultralight overnight trips with compact gear.

35–50 litres — Weekend and overnight trips. Enough space for a lightweight tent or shelter, sleeping bag, sleeping mat, stove, food, and clothing for one to three nights. Also suitable for winter day hikes where bulkier clothing and additional safety equipment are required.

50–70 litres — Multi-day backpacking. The standard capacity for trips of three to seven days carrying full camping equipment, food, and clothing. This is the most versatile size range for regular backpackers.

70–85+ litres — Extended expeditions, winter backpacking with bulky gear, or trips requiring heavy food carries between resupply points. Only necessary if you are carrying substantial weight over many days.

A common mistake is buying a pack that is too large. Excess capacity psychologically encourages overpacking — "there is room, so I might as well bring it." Every extra item adds weight. Experienced backpackers frequently find that their pack size decreases over the years as they refine their gear choices and learn what they actually need.

Types of Backpacks

Daypacks

Small packs (10–35 litres) designed for single-day outings. They typically have simple suspension systems, padded shoulder straps, and may include a hip belt for stability. Features are focused on accessibility and lightweight comfort.

Hiking and Trekking Packs

Mid-range packs (35–60 litres) with more substantial hip belts, adjustable shoulder straps, and often an internal frame. Designed for carrying moderate loads over longer distances, with padding and support systems that increase comfort under weight.

Backpacking and Expedition Packs

Large packs (50–85+ litres) with full internal frames, heavily padded hip belts, multiple adjustment points, and robust suspension systems. Designed to carry heavy loads (15–25 kg / 33–55 lbs) comfortably over multiple days.

Ultralight Packs

Minimalist packs (30–60 litres) that sacrifice padding, pockets, and frame features to achieve the lowest possible empty weight. Typically best suited to experienced backpackers who have already minimised their gear weight — an ultralight pack becomes uncomfortable if overloaded.

Trail Running Packs and Hydration Vests

Close-fitting packs (5–20 litres) designed for running. They prioritise stability (no bouncing), breathability, and accessibility. Many have front-facing pockets for water bottles or soft flasks.

Frame Types — Internal, External, and Frameless

Internal Frame Packs

The standard for modern backpacking. One or two aluminium or carbon fibre stays sit inside the pack, close to your back, transferring load to the hip belt. Internal frame packs ride close to the body, offering excellent balance and stability on uneven terrain. They are the best choice for most hiking and backpacking situations.

External Frame Packs

A visible metal frame (usually aluminium tubing) sits outside the pack bag, with the bag attached to the frame. External frames provide excellent ventilation (the pack bag sits away from your back) and carry heavy, awkward loads well. They are less common than they once were but remain popular for certain uses, including portaging canoes and carrying very heavy loads on well-maintained trails.

Frameless Packs

Ultralight packs that omit the frame entirely, relying on the packed contents to provide structure. A folded sleeping pad often serves as a makeshift frame sheet. Frameless packs are the lightest option but transfer weight less effectively and are only comfortable with lighter loads — typically under 10 kg (22 lbs) total.

Suspension Systems Explained

The suspension system is the complete assembly of components that connects the pack to your body: the shoulder harness, hip belt, back panel, load-lifter straps, sternum strap, and frame. A well-designed suspension distributes weight between your hips and shoulders, allows adjustment for different loads and terrain, and keeps the pack stable against your body.

Premium suspension systems offer multiple adjustment points — torso length adjustment, hip belt angle, shoulder strap width, and load-lifter tension. Mid-range packs typically offer fixed torso length with adjustable straps. Budget packs may offer minimal adjustment.

Some modern suspension systems feature a trampoline-style mesh back panel that holds the pack body away from your back, creating an air gap for ventilation. This significantly reduces the sweaty-back problem common with traditional close-fitting designs, though it does add a small amount of bulk and can shift the pack's centre of gravity slightly rearward.

Measuring Your Torso — The Non-Negotiable Step

Pack size is determined by your torso length, not your overall height. Two people of the same height can have significantly different torso lengths, and a pack that fits one may be completely wrong for the other.

To measure your torso length, you need a helper and a flexible measuring tape.

Tilt your head forward and feel for the bony bump at the base of your neck where your neck meets your shoulders. This is your C7 vertebra — the top of your torso measurement.

Place your hands on your hips with your thumbs pointing backward. Draw an imaginary line between your thumb tips across your lower back. The point on your spine at this line is approximately your iliac crest — the bottom of your torso measurement.

Measure the distance between these two points along your spine. This is your torso length.

Most pack manufacturers offer sizing charts that match torso length to pack size (typically small, medium, large, or sometimes extra small to extra large). Some packs offer adjustable torso lengths, which can accommodate a range of measurements — useful if the pack may be shared between people.

Hip Belts — Where the Real Carrying Happens

The hip belt should carry approximately eighty per cent of the pack's weight. This transfers the load from your shoulders and spine to your pelvis and legs — the strongest load-bearing structures in your body.

An effective hip belt wraps around the top of your hip bones (the iliac crest), not your waist. It should be snug, well-padded, and comfortable under load. The padding should be firm enough to support weight without collapsing, but soft enough to avoid pressure points.

Some packs offer removable or interchangeable hip belts in different sizes, which is valuable if your hip circumference does not match the torso size. Check that the hip belt size is adequate — if the belt is too small, it will not close properly; if too large, the padding will sit incorrectly.

Hip belt pockets — small zippered pockets on the belt wings — are one of the most useful features on any backpack. They keep snacks, a phone, lip balm, and other frequently accessed items within reach without stopping.

Shoulder Straps, Load Lifters, and Sternum Straps

Shoulder straps should follow the contour of your shoulders and sit comfortably without digging in or slipping off. They carry a relatively small percentage of the total load (most is on the hips) but are critical for stability and balance.

Load-lifter straps connect the top of the pack frame to the tops of the shoulder straps. When tightened, they pull the top of the pack closer to your body, preventing it from leaning away and pulling you backward. The ideal angle for load lifters is approximately 25–45 degrees from horizontal. If the angle is too steep or too shallow, the pack torso length may not match yours.

The sternum strap connects the two shoulder straps across your chest. It prevents the shoulder straps from slipping outward and helps distribute load across the chest. It should sit roughly at mid-chest level — not pressing on the throat and not riding too low.

Back Panels and Ventilation

The back panel is the interface between the pack and your body. Designs range from flat, foam-padded panels (which sit close to the body for efficient load transfer) to tensioned mesh panels (which create an air gap for ventilation).

In warm weather and on strenuous hikes, a ventilated back panel dramatically reduces perspiration and discomfort. The trade-off is a slightly increased packed depth and a marginal shift in the pack's centre of gravity away from your back.

For cold-weather hiking, where body heat loss is the concern rather than overheating, a close-fitting padded panel may be preferable.

Access — Top-Loading, Front-Loading, and Panel Access

Top-loading packs access the main compartment through a drawstring closure at the top, usually secured with a lid (brain). This is the most common design for backpacking packs. The drawback is that items buried at the bottom require you to remove items above them.

Front-loading (panel-access) packs feature a zip that opens the entire front face of the pack, similar to a suitcase. This makes accessing specific items much easier and is popular for travel packs. The zip adds weight and a potential point of failure under heavy loads.

Bottom compartments — separated from the main compartment by a divider — provide direct access to items stored at the bottom (typically a sleeping bag). This is a practical feature for backpacking packs and avoids the need to unpack everything to reach your sleeping gear.

Some packs combine all three access methods, offering maximum versatility at a modest weight cost.

Pockets, Compartments, and Organisation

The right number of pockets is enough to organise your essential items without adding unnecessary weight and complexity. Key pocket types include:

Lid pocket — sits on the top flap (brain) of a top-loading pack. Ideal for items you need throughout the day: snacks, sunscreen, map, head torch.

Side pockets — typically stretch-mesh, used for water bottles, tent poles, or items you want to grab without removing the pack.

Hip belt pockets — small, zippered. Essential for snacks, phone, and lip balm on the move.

Front stretch pocket — a large mesh or fabric pocket on the front face. Useful for drying wet clothing, stashing a rain jacket for quick access, or holding items that do not fit inside.

Internal hydration sleeve — a dedicated space for a water bladder, with a port for the drinking tube.

Base compartment — a separate lower section, often used for a sleeping bag.

Compression Straps and Attachment Points

Compression straps pull the pack body inward, reducing volume when the pack is not fully loaded. This keeps the contents stable and prevents shifting, which improves balance and comfort. Side compression straps are standard; some packs also have vertical or front compression.

Attachment points include daisy chains, gear loops, and lash points for securing items to the exterior of the pack — ice axes, trekking poles, sleeping mats, or helmets. These are more important for technical hiking and mountaineering than for general backpacking.

Trekking pole loops — elastic loops or straps for carrying trekking poles when not in use. A small but appreciated feature.

Hydration Compatibility

Most modern backpacks include a dedicated sleeve or pocket for a hydration bladder (reservoir), with a port for the drinking tube to exit the pack near the shoulder. Using a hydration bladder allows you to drink on the move without stopping to retrieve a water bottle — a genuine advantage on long or hot hikes.

If you prefer water bottles to a bladder, ensure the side pockets are accessible while wearing the pack and large enough for your preferred bottle size.

Rain Covers and Weather Protection

Many backpacks include an integrated rain cover — a waterproof sheet that stretches over the exterior of the pack. Some are stored in a dedicated pocket at the base of the pack for quick deployment.

Rain covers protect against moderate rain but are not fully waterproof — water can still enter between the cover and your back, through the base, or in sustained heavy rain. For reliable waterproofing in serious conditions, use a waterproof pack liner (a large dry bag inside the pack) in addition to or instead of an external cover.

If your pack does not include a rain cover, aftermarket covers are available in various sizes and are worth the small investment.

Pack Weight — The Empty Weight Debate

The empty weight of a pack matters, but it must be evaluated in context. A lighter pack with minimal padding, a thin hip belt, and no frame will be uncomfortable under heavy loads. A heavier pack with robust suspension will carry a heavy load more comfortably, and that comfort translates to less fatigue, fewer rest stops, and a better experience.

The practical approach is to match pack weight to your typical load. If your total packed weight (including food, water, and gear) is under 10 kg (22 lbs), a frameless or ultralight pack saves meaningful weight. If your total packed weight is 15–25 kg (33–55 lbs), the additional weight of a proper frame and padded suspension is a worthwhile investment in comfort and safety.

As a general guide, aim for an empty pack weight of 1.0–1.5 kg (2.2–3.3 lbs) for ultralight use, 1.5–2.5 kg (3.3–5.5 lbs) for standard backpacking, and up to 3 kg (6.6 lbs) for expedition packs designed to carry very heavy loads.

Fitting and Adjusting Your Pack

Once you have a pack that matches your torso length, the fine adjustment process makes the difference between adequate and excellent fit.

Load the pack with approximately the weight you will typically carry. Put it on and fasten the hip belt first, centring it on your iliac crest. Then adjust the shoulder straps so they follow your shoulder contour without gaps. Tighten the load-lifter straps to bring the top of the pack closer to your body. Clip and adjust the sternum strap across your chest.

Walk around — ideally on varied terrain including inclines — and assess how the pack feels. The weight should be primarily on your hips. Your shoulders should feel mild pressure from the straps but not be bearing significant weight. There should be no pinching, rubbing, or pressure points.

If the pack has an adjustable torso length, experiment with small adjustments while loaded. Even a centimetre of torso adjustment can noticeably improve comfort.

Packing Your Backpack — Weight Distribution Basics

How you pack your backpack affects balance, comfort, and access to your gear.

Bottom layer: Sleeping bag, sleeping clothes, and items you will not need until camp. These are lightweight and compressible, forming a base.

Core (close to your back): Heavy, dense items — food, water, stove, fuel. Keeping heavy items close to your back and at mid-height maintains your centre of gravity and improves balance.

Top and outer: Items you need during the day — rain jacket, snacks, head torch, first aid kit. The lid pocket is ideal for the most frequently accessed items.

Exterior: Sleeping mat, trekking poles, wet items drying in the sun. Keep exterior items secured and minimal to avoid snagging on vegetation and shifting your centre of gravity.

The Honest Limitations

No pack fits everyone perfectly. Torso lengths, hip shapes, shoulder widths, and body proportions vary enormously. A pack that receives universal praise may not work for your specific body. The only reliable test is trying it on with weight.

Online purchasing is difficult for packs. Fit cannot be assessed from a screen. If buying online, choose retailers with generous return policies and be prepared to try multiple options.

Bigger is not better. A larger pack invites overpacking. Choose the smallest pack that comfortably holds your gear.

Ultralight packs have limits. Below a certain level of structure and padding, comfort under load degrades significantly. Ultralight packs work best for ultralight loads.

Waterproofing is your responsibility. Very few packs are inherently waterproof. Pack liners and rain covers are necessary additions, not optional.

Choosing the Right Backpack for You

Your Pre-Purchase Checklist

Measure Your Torso

This is non-negotiable. Measure your torso length and use the manufacturer's sizing chart to select the correct size.

Define Your Typical Trip Length

Choose capacity based on how long you are usually out for, not the longest trip you might theoretically take.

Try With Weight

If possible, load the pack with your typical weight and walk with it before committing. Many outdoor retailers have weighted sandbags for this purpose.

Check the Hip Belt Fit

The hip belt should centre on your iliac crest and close comfortably with room for adjustment. If the belt does not fit, the pack does not fit — regardless of other features.

Assess Ventilation

If you hike in warm climates or sweat heavily, a ventilated back panel makes a significant comfort difference.

Consider Access

If you dislike unpacking to reach buried items, prioritise a pack with panel access or a sleeping bag compartment.

Plan for Weather

Ensure the pack either includes a rain cover or is compatible with one. Consider a pack liner for guaranteed waterproofing.

Buy Last

Acquire your tent, sleeping bag, sleeping mat, and other bulky items first. Then choose the smallest pack that fits them.

Why Buying Through Amazon Is a Smart Option

Amazon carries an extensive range of backpacks from every major outdoor brand, across all capacity ranges and price points. Customer reviews provide real-world feedback on fit, comfort, durability, and feature usefulness from hikers with a wide variety of body types and trip styles. The returns process is straightforward — particularly valuable for a purchase where fit is critical.