What Size Rucksack Do I Need?

Rucksacks are measured by their capacity in litres, and the size you need depends on the activity and amount of equipment you plan to carry.

10–25 litres: Ideal for day walks and everyday outdoor use. These smaller daypacks have enough space for food, water, waterproof clothing and essential walking gear.

25–35 litres: Suitable for longer mountain days, mountaineering, climbing and lightweight overnight trips. They provide space for extra clothing, climbing equipment, a confidence rope, ice axe or crampons.

35–50 litres: A versatile choice for lightweight backpacking, winter climbing and alpine trips. The additional capacity is useful for carrying more technical equipment, or lightweight camping equipment such as a tent and sleeping bag.

50 litres and above: Designed for backpacking, expeditions and travelling where you need to carry a tent, sleeping bag, sleeping mat, cooking equipment and additional clothing.

Remember that bigger isn't always better. A larger rucksack can encourage you to carry unnecessary equipment, adding weight to your load.

Getting the Right Rucksack Fit

The most important consideration when choosing a rucksack is fit. Your rucksack should match your torso length rather than simply your overall height.

Your torso measurement is taken from the C7 vertebra at the base of your neck to the centre of your iliac crest, at the top of your hips. Getting this measurement right helps ensure the rucksack sits correctly and distributes weight comfortably.

Some rucksacks have a fixed back length, which is common on lightweight daypacks, climbing packs and mountaineering rucksacks. Others feature an adjustable back system, allowing you to alter the length to suit your body. Adjustable systems are particularly useful on larger hiking, trekking and backpacking rucksacks where heavier loads are carried.

Men's and Women's Rucksacks

Many manufacturers produce men's and women's versions of their rucksacks, with differences in back length, shoulder straps and hip belt design to reflect typical body shapes.

However, these are guidelines rather than rules. Body shape and stature vary considerably, so the best rucksack is the one that fits you correctly. Trying different packs with some weight inside is the best way to find the right fit.

How Should a Rucksack Fit?

A correctly fitted rucksack should transfer most of its weight through your hips rather than your shoulders. As a general guide, around 80% of the load should be carried through the hip belt and 20% through the shoulders.

Start by positioning and fastening the hip belt comfortably around your hips. Adjust the shoulder straps so the pack sits securely without creating pressure points. Next, adjust the load-lifter straps so they are under tension, followed by the sternum strap to keep the shoulder straps comfortably positioned.

Using a mirror can help you check that the shoulder straps sit correctly and that the load-lifter straps are positioned at approximately 45 degrees.

Which Rucksack Features Do I Need?

Once you've found a rucksack that fits correctly, consider the features you actually need.

For walking in wet weather, look for an integrated rain cover or consider using a waterproof liner. Climbers may want dedicated helmet storage, ice axe attachments and easy-access gear loops. Hip belt pockets are useful for keeping small essentials such as snacks, a phone or compass close at hand.

If you regularly use your rucksack in winter, make sure buckles and attachment points are easy to operate while wearing gloves.

Try Before You Buy

The best way to choose a rucksack is to try it with some weight inside. Walk around, climb stairs and test it on an incline if possible. A rucksack that feels comfortable when empty may feel very different when fully loaded.

Fit should always come first, followed by capacity and features. Choose a rucksack designed for your activity, get the correct torso size and take time to adjust it properly. With the right fit and capacity, your rucksack will become an essential and comfortable part of your outdoor kit.