Walking boots: ankle height, sole stiffness and B0 to B3 ratings

Saturday morning, the boot wall of an outdoor shop: forty pairs in a row, labels reading ‘B1’, ‘B2’ and ‘A/B’ that belong in the vitamin aisle, and a shop assistant asking where you plan to walk. It’s the only question that matters: boots are chosen for the ground, not for the colour or the promise on the box.

It isn’t just about comfort. In Scotland, a slip or trip played a part in 152 of the 491 mountaineering incidents attended by mountain rescue teams in 2025, more than any other factor, according to Scottish Mountain Rescue. The ankle was the most common injury site [1]. In Switzerland, the Council for Accident Prevention (BFU) puts most mountain walking accidents down to trips and slips. It asks for sturdy boots with a non-slip, well-treaded sole [2], and Mountaineering Scotland for soles that grip on rock, grass and mud [3].

The upper: low, mid or high cut

The upper wraps your foot and ankle. Approach shoes or soft fabric boots are fine on simple tracks, says Mountaineering Ireland. Rougher ground, especially in poor weather, calls for a sturdier mountain walking boot: water resistant, with an aggressive tread, medium ankle support and, above all, a sole that resists twisting. Fabric boots often grip poorly on wet, grassy slopes, and in winter, light fabric boots or trainers greatly increase the risk of a slip or fall [4].

The BFU sorts boots the same way: light walking shoes for yellow-waymarked paths, trekking boots that wrap the ankle for mountain paths, stiff mountain boots that take crampons for alpine routes [2]. A mid-cut boot is a compromise. The German Alpine Club (DAV) notes that the soft, mid-height cuff of light mountain boots gives mobility, but little support under a very heavy rucksack [5]. The heavier the load and the rougher the ground, the higher the cut.

The sole: grip and stiffness

Two qualities count underfoot. Grip first: a non-slip sole with a well-defined tread, as the BFU asks [2].

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Then stiffness. A flexible sole bends with the path, comfortable on easy ground; a stiff sole shields your foot from stones, holds on the edge of a step and takes crampons. Most summer walking boots are designed to flex for comfort: their midsole isn’t rigid enough for crampons, and softer uppers can compress under crampon straps, causing discomfort and cold feet, explains the British Mountaineering Council (BMC) [6]. That’s why, in the categories below, the sole stiffens as the cuff rises [5].

The A to D categories: a European yardstick

Many boot labels also carry a letter from A to D. The German Alpine Club explains that walking and mountain boots are sorted by use into these categories, introduced in the 1970s. Category A covers models with a soft sole and a low cut, comfortable on easy paths; category D, models with a stiff sole and a high, stable cuff, for hard routes in the Western Alps or expeditions [5]. Intermediate categories sit in between. The German maker Meindl says the system was devised within the family firm in 1975 to classify its boots, and that many manufacturers now use it. Its UK site sets out the grid like this [7]:

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These categories are a manufacturer’s yardstick: they describe the use each maker intends for its own models [7]. Between two categories, choose for your most demanding walk, not your most frequent one. Meindl’s advice runs the same way: if in doubt, go for the sturdier boot, which covers a wider range of uses [7]. And look closely at light mountain boots, which are hard to classify because they blend stability and agility, notes the DAV [5].

Crampons and the B0 to B3 ratings

Crampons only go on boots designed for them: if the sole isn’t stiff, the boot bends and the crampon can fall off, warns the BMC. It rates walking boots from B0 to B3 and crampons from C1 to C3, and calls a B1 boot the absolute minimum for crampons [6]:

On the crampon side, a C1 is a flexible walking crampon held on with straps and toe and heel baskets, and a C3 a technical climbing crampon fixed with a heel clip [6]. Micro-spikes are no substitute on serious ground. The BMC keeps them for flat or gently sloping paths with ice or compacted snow, and warns that they often won’t give enough security where a slip could become a long slide or a fall [6].

On the A to D scale, Meindl’s grid starts crampons at B/C, for occasional use [7], and the DAV rates light mountain boots as conditionally compatible with semi-automatic crampons [5]. When you buy crampons, take your boots along, says the BMC: the two must suit each other and be adjusted together [6].

Fitting and breaking in

Try boots on in the afternoon or evening: your feet swell a little over the day, as they do at the end of a walk, say Mountaineering Ireland, Meindl and the DAV [4, 7, 5]. The DAV suggests walking around in them for at least 10 to 15 minutes, the only way to tell whether they really fit [5]. Mountaineering Ireland adds a slope to walk up and down, and a loaded rucksack, which changes the shape of your foot [4]. Every maker builds on its own lasts, the foot-shaped forms a boot is made around, and they can vary between models [5]: there’s no skipping the fitting. Back home, Meindl suggests wearing them indoors first to check the size [7].

New boots need wearing in. Mountaineering Ireland suggests breaking in stiffer boots on progressively longer walks, and calls it very risky to take new boots on a long trek [4]. The BFU adds good walking socks to reduce the risk of blisters [2]; AdventureSmart UK prefers breathable ones, merino wool ideally, rather than cotton [8]. At the first hot spot, act at once, says Mountaineering Ireland [4]. Our day walk kit list keeps a first aid kit within reach for exactly that.

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The right boot is neither the dearest nor the tallest: it’s the one that suits the ground of your next walk, tried on in the afternoon and already shaped to your foot. For the rest of the preparation, our guide to planning a hike takes you through it step by step, and our guide to mountain walking grades tells you what the ground will look like.

Worth watching

Icicle, based in Windermere, explains what B1, B2 and B3 boots are for and the kinds of route each one suits, to go with this guide’s section on boot ratings and crampons.

The video is hosted by YouTube (Google): nothing loads until you play it, and Google may then set cookies.

Guillaume Hoarau

Camping, wild camping, bushcraft and hiking

Guillaume Hoarau writes for Outfarer about camping, wild camping, bushcraft and hiking. A survival-skills enthusiast and a collector of old field manuals, he likes clear explanations, lists that earn their place and other people’s stories, which he tells well.

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