The Swiss Alpine Club hiking scale runs from T1 to T6 and is the standard way alpine paths are graded across Switzerland, Austria, Germany and increasingly elsewhere. It appears on signposts, in guidebooks, in hut wardens' advice and in the mapping data behind most route planners, including this one.
It is worth ten minutes of your attention, because the step from T3 to T4 is where a walk stops being a walk.
The grades
T1 - Hiking (Wandern) Well-made path, no exposure, no risk of falling. Trainers are fine. Suitable for anybody who can walk. Valley paths, well-graded approaches, the walk in from the car park.
T2 - Mountain hiking (Bergwandern) Continuous path, sometimes steep, terrain that requires sure-footedness. Boots wanted. No hands needed. This is the ordinary currency of alpine walking and most of what a hut-to-hut route consists of.
T3 - Demanding mountain hiking (anspruchsvolles Bergwandern) Path may not be continuous. Exposed sections may be protected with cables or chains. Hands used occasionally for balance. Requires a head for heights. This is the grade where people who are perfectly happy on T2 start to find out something about themselves.
T4 - Alpine hiking (Alpinwandern) Path frequently absent. Route-finding required. Exposed terrain, easy scrambling, and possibly snow slopes or glacier remnants. Requires alpine experience and an ability to assess terrain, not just fitness. This is the boundary: below it you are walking, at and above it you are mountaineering in a small way.
T5 - Demanding alpine hiking (anspruchsvolles Alpinwandern) Frequent scrambling, significant exposure, often glacier travel. Requires the equipment and skills to match, including rope work in places.
T6 - Difficult alpine hiking (schwieriges Alpinwandern) Serious scrambling and climbing, considerable exposure, glaciers with real crevasse risk. Mountaineering with a rucksack.
What the grades actually look like out there
We compute the terrain grade of every leg between huts in our network, using the gentlest available line between each pair. Across 9,092 hut-to-hut legs in 13 regions of the Alps and Pyrenees, covering about 176,600 km of measured ground, the split is:
- T2 - 44.7% of all distance
- T1 - 25.3%
- Roads and tracks - 17.3%
- T3 - 7.2%
- T4 - 1.6%
- T5 - 1.5%
- T6 - 0.6%
- Glacier crossings - 1.9%
Two things stand out.
The overwhelming majority of hut-to-hut ground is T1 and T2. Seventy per cent of the distance is straightforward mountain walking, and another 17% is road or track. The hard grades are a rounding error by distance.
But distance is the wrong measure. Grading each leg by its hardest section rather than its average tells a different story:
- 39.7% of legs top out at T2
- 37.5% top out at T3
- 8.6% reach T4
- 7.0% reach T5
- 3.7% reach T6
So roughly one leg in five has at least a T4 section on it, even though T4 and above account for under 4% of the walking distance. A hard grade is typically a short passage - one col, one gully, one exposed traverse of a few hundred metres - embedded in an otherwise ordinary day.
That is the practical lesson of the whole scale. A route is graded by its worst moment, not its average, and the worst moment is usually brief and usually near the top.
Glacier and via ferrata are separate questions
The SAC scale describes difficulty. It does not describe hazard, and conflating the two is a mistake we deliberately avoid.
Glacier crossings appear on 11.2% of the legs we measure - about one in nine - while making up under 2% of total distance. A glacier is not "harder walking"; it is a different activity requiring a rope, crevasse rescue skills and a partner, and a dry T4 col and a glaciated T4 crossing are not remotely the same proposition. We record glacier separately and let you exclude it outright rather than folding it into a difficulty number.
Via ferrata is rarer than people expect. Only 0.4% of the legs we measure touch a via ferrata section at all. Where they do, the grade is its own scale entirely - see via ferrata grades explained.
Using it to plan
Know your ceiling honestly. Most people walking hut to hut are comfortable to T3 and should treat T4 as a decision rather than a detail. If you have never used your hands on a mountain, T3 is your realistic ceiling for a first trip.
Check the hardest section, not the average. A leg described as "mostly T2" can still contain the passage that stops you. This is why we show the breakdown by grade for each leg rather than one number.
Ask the warden. Grades are static and conditions are not. A T3 col with old snow on it in early July is a different place from the same col in September, and the person who runs the hut below it will know today's answer.
Have a fallback. If a leg is at your limit, know before you set off what you will do if it turns out to be beyond it, because turning back late in the day on an alpine traverse is its own problem.
HutScanner shows the terrain grade breakdown for every leg between huts, marks glacier and via ferrata sections separately, and lets you set a difficulty ceiling so routes above your grade are filtered out rather than quietly suggested. Routes are computed estimates over open mapping data, not surveyed trails - check them against an official map and against local advice. You book directly with each hut; we are a planning aid, not a booking service.