The 11 Tour du Mont-Blanc variants, measured one by one (and what they really cost)

Out on the Tour du Mont-Blanc, people often size up a variant with the wrong measure altogether. The question we hear most is how many kilometres it adds, but on this trail distance tells you almost nothing useful. Once you measure all eleven tracks properly, three of them actually come out shorter than the route they replace: the Petit Col Ferret by 4 km, the col des Fours also by 4 km, and the Fenêtre d'Arpette by 3 km. The first two barely cost anything extra in climbing either. The third, though, piles on 425 more metres and stays the hardest day of the whole tour.

At Altimood, we bring groups out on this route and we record the tracks ourselves, season after season. This piece lines up all eleven usable variants against the section they replace, with the real difference in distance, elevation gain and walking time, each one with its own GPX track to download.

One thing worth saying before we get into the numbers: "worth the detour" isn't something you can measure, it's an opinion. Ours depends on the morning weather, how the group is holding up, and what we've already seen on the days before. The numbers themselves don't shift, though, and that's what lets us have the rest of this conversation on solid ground.

The 11 variants compared to the classic route

Each row here compares a variant to the exact stretch it replaces, with matching start and end points either side. The figures come off our own tracks, smoothed the same way as the elevation profiles further down the page. Time is worked out for a steady walker with a trekking pack, around 370 m of climbing an hour.

The order here runs by elevation cost, cheapest to priciest, not by distance. That's the number that actually matters on a multi-day trek: you can make up kilometres, but metres of climbing keep adding up day after day.

So take both columns together, never one on its own. The Fenêtre d'Arpette makes the point nicely: 3.3 km shorter, and still the hardest day on the whole circuit, because it throws in 425 extra metres over a scree slope. The col des Fours, on the other hand, is the only variant that comes out negative on both counts, and the Petit Col Ferret isn't far off either, its extra thirty-five metres of climbing barely worth mentioning. Those two are the real bargains of the tour.

The table also clears up a question we get a lot: where the tour's highest point actually is. On the main route, the TMB tops out at the Grand Col Ferret, 2,537 m. Bring the variants into it, and the highest ground you'd actually walk on any single itinerary is the Mont-Fortin traverse, around 2,730 m, on the mountain's flank rather than its top. Higher again, but as a there-and-back rather than part of the tour itself, the Tête Nord des Fours (2,756 m) is twenty minutes from the col des Fours: it's the highest spot your boots will ever touch on the whole route. And two passes share the exact altitude of 2,665 m, the col des Fours and the Fenêtre d'Arpette, one in France, the other in Switzerland. The "high point" column gives the official altitude of the place itself, which our tracks come within a few metres of, except where the path deliberately dips below the summit.

What a variant really costs

The classic TMB comes in around 170 km for roughly 10,000 m of elevation gain. String together the six high-altitude variants, col du Tricot, col des Fours, Mont-Fortin, Mont de la Saxe, Fenêtre d'Arpette and Lac Blanc, and the distance hardly changes at all, while the elevation gain climbs by about 1,800 m.

And that's really the whole story. On this trail, you don't pay for a variant in kilometres, you pay for it in climbing. The high paths cut straight over the passes while the main route swings round lower down, so you end up walking a touch less distance but a good deal more height. Across the whole tour, the gap in distance comes to a few hundred metres at most, which is nothing really, well below what any GPS track can even tell apart.

The 1,800 m of climbing, though, that you'll feel. It works out at nearly 20% more effort across the whole trip, and it stretches out the days even when the map says the distance hasn't budged. A tour with every variant included is a good deal harder than one without, no two ways about it. What the numbers give you is simply knowing where to look: the elevation column, not the kilometre one.

So the decision really comes down to your legs, your timetable, and the day after. To see what those 1,800 metres do to your own schedule, our TMB duration calculator builds in all eleven variants from this article and works out the nights accordingly, allowing for which places to stay each one rules out.

The variants that cost almost nothing

Four variants can be slotted in without reshuffling the day at all. They add under 100 metres of climbing between them, and one actually takes some away.

The col des Fours, 2,665 m, stage 2

This is the only variant on the whole tour that's both shorter and less climbing than what it replaces: 3.8 km and 40 metres of elevation gain less. It comes down to the lie of the land. From the refuge de la Croix du Bonhomme, the classic path drops 900 metres to Les Chapieux, right down in the valley floor, before climbing back up 320 metres to Les Mottets. The variant, instead, just keeps going another 190 metres to the col des Fours, then drops straight into the vallée des Glaciers and picks up the TMB again further along.

So you're walking less to end up higher. The view from the pass, at 2,665 m, takes in the Écrins to the south and the Mont-Blanc massif to the north. If you've the time and the sky's playing along, an easy shoulder carries on due north from the pass to the Tête Nord des Fours (2,756 m) in about twenty minutes, the best viewpoint around.

What this variant really costs you is the night at Les Chapieux. The hamlet is a resupply stop and one of the few places round here where you can actually sleep, and the col des Fours skips it entirely. It's as much a scheduling decision as a route one, and it's one to make when you're booking, not on the morning itself.

The other thing to watch is the weather. At 2,665 m on a shoulder with no shelter, a storm is something you just have to ride out. The snow patch on the way down to the Ville des Glaciers often lingers until early July, and that steep drop is what eats into, on the ground, the theoretical 55-minute head start. Expect it to take roughly the same time as via Les Chapieux, just with a different view.

• Distance :↔ 5.9 km
• Dénivelé positif :↗ 228 m
• Dénivelé négatif :↘ 873 m

The full rundown of the day, and how it stacks up against the classic descent, is in stage 2, Les Contamines to Les Chapieux.

The Petit Col Ferret, 2,490 m, stage 6

Here's the best bargain on the whole tour, and by far the least known about. Between the Rifugio Elena and La Fouly, the Petit Col Ferret (2,490 m) comes in 3.7 km shorter than the classic Grand Col Ferret passage, for just thirty-five extra metres of climbing. Thirty-five metres is nothing, really, barely measurable. So that's close to four kilometres and three-quarters of an hour handed to you for free.

The reason is in the descent, not the climb. The classic pass drops onto the alpage de La Peule and follows the whole upper Swiss Val Ferret before reaching La Fouly. The Petit Col Ferret, forty metres lower and a kilometre further west, drops more directly into the valley. On the track it passes two and a half kilometres from La Peule without ever seeing it.

That's also what makes the choice less obvious than it first looks. The Swiss side of the Petit Col Ferret is steeper and much quieter, the path narrower underfoot, and the alpage de La Peule you're skipping is one of the loveliest stops on the Swiss side, cheeses and terrace included. You gain time, but you're giving up a break plenty of walkers list among their favourite memories of the whole trip.

Our honest take: it's worth it on a day when time is short, or when the weather's closing in and you need to get down early. On an ordinary day, La Peule earns its four kilometres.

• Distance :↔ 7.9 km
• Dénivelé positif :↗ 488 m
• Dénivelé négatif :↘ 926 m

The classic route via the Grand Col Ferret (2,537 m), the high point of the main route, is covered in stage 6, refuge Bonatti to La Fouly.

The Mont-Fortin, 2,758 m, stages 3 and 4

Ninety extra metres of climbing and four hundred extra metres of distance, for a near-continuous ridge walk above the Val Veny. On paper, it's the best bargain going.

Out on the ground, though, it's the most committing variant on the whole list, and the table won't tell you that. It kicks off right after the col de la Seigne, takes in the col des Chavannes (2,598 m), the flank of the Mont-Fortin, then the col de Youla (2,661 m), before dropping to the Col Chécrouit. Nearly the whole thing sits above 2,500 m, well away from anywhere, with no way out once you're committed. Our track tops out at 2,730 m.

It's closer to a high-route traverse than a TMB variant. We'd only bring this out with groups already well used to altitude, in settled weather, with plenty of time in hand. The real cost isn't in the 90 metres, it's in the commitment.

This one also bypasses the Rifugio Elisabetta, the natural place to stay for this stretch, so it reshapes how stages 3 and 4 are split.

• Distance :↔ 18.5 km
• Dénivelé positif :↗ 1151 m
• Dénivelé négatif :↘ 1124 m

The classic passage below the Mont-Favre ridge is covered in stage 4, Rifugio Elisabetta to Courmayeur.

The ladder bypass, stage 10

This one isn't really about scenery, it's a solution. The eleven metal ladders at Trè-le-Champ put a good few walkers off, and there's a waymarked path that skirts round them via the col des Montets. It adds 2.1 km and only 85 metres of climbing.

Its real value is elsewhere: measured on the track, this bypass rejoins the TMB at the Tête-aux-Vents (2,132 m), which sits before the Lac Blanc turn-off, not after. So skipping the ladders doesn't cost you the lake, whatever the map seems to suggest at a glance.

• Distance :↔ 8.2 km
• Dénivelé positif :↗ 771 m
• Dénivelé négatif :↘ 329 m

The circuit's other exposed sections and how to get round them are covered in our article on the Tour du Mont-Blanc for anyone who doesn't love heights.

The variants that cost an hour or two

Three variants fit inside a morning's head start. You decide on these on the day itself, with an eye on the sky.

The Aiguillettes des Houches, 2,285 m, stage 11

On the final day, rather than dropping straight from Bellachat to Les Houches, you carry on along the Aiguillettes des Houches ridge before heading down. The variant adds 3.4 km and 180 metres of climbing, around 1h15.

It's the least popular of the eleven, which makes sense really: on day eleven you've a train to catch, sore legs, and the tour already wrapped up in your mind. It's mostly worth it if you're finishing early and fancy stretching out that last descent rather than just getting it over with. This side is also a good deal quieter than the direct path.

• Distance :↔ 9.4 km
• Dénivelé positif :↗ 178 m
• Dénivelé négatif :↘ 1330 m

The classic route via the Brévent is covered in stage 11, La Flégère to Les Houches.

The Lac Blanc, 2,352 m, stage 10

The most photographed detour in the whole of the Alps costs 1.7 km and 285 metres of climbing from the Tête-aux-Vents, around 1h30 there and back. The lake's milky colour comes from rock ground down by the glacier over the years, and the reflection of the Drus in the first pool is the shot everyone's seen.

It's the most weather-dependent variant on the tour by far. Under a clear sky, it's easily worth the hour and a half. Under low cloud, you're left with a grey lake and a climb for nothing, so the energy's better saved. It's also the only one on this list you can leave until the very last second, since the turn-off is right at the cairn on the Tête-aux-Vents, sky in full view.

Given stage 10 is the shortest on the whole circuit, this detour almost never causes any bother with timing.

• Distance :↔ 7.8 km
• Dénivelé positif :↗ 973 m
• Dénivelé négatif :↘ 533 m

The lake also makes a grand day out on its own, away from the TMB: see our article on Lac Blanc from Chamonix.

The Prarion, 1,967 m, stage 1

Setting off from Les Houches, instead of climbing to the col de Voza on the GR path, you follow the GRP Tour du Pays du Mont-Blanc up to the top of the Prarion (1,967 m), then drop back down to the col de Voza. The variant adds 4.6 km and 300 metres of climbing, the longest add-on on the whole list, though not the toughest.

Its appeal is as much about the company as the view. Day one of the TMB is when you'll cross paths with the most people, since everyone leaves Les Houches around the same time. The Prarion side sits away from all that, and away from the lifts too, climbing through shaded forest before opening onto a full 360-degree view over the Mont-Blanc massif, the Chamonix valley and the Aravis.

Worth knowing about if you're setting off in peak season and the first day's crowds are on your mind.

• Distance :↔ 12.6 km
• Dénivelé positif :↗ 1007 m
• Dénivelé négatif :↘ 660 m

The variants that cost half a day

The last four will cost you. They need the day planned around them, not a decision made over breakfast.

The Fenêtre d'Arpette, 2,665 m, stage 8

This is the big call on the Swiss side. Between Champex-Lac and Trient, the Fenêtre d'Arpette comes in 3.3 km shorter than the Bovine route, and that's the number that catches everyone out. It doesn't make the day any easier for it, mind: it climbs 425 metres more, all of it on a scree slope, and it stays the toughest day of the whole circuit. Walking less while climbing more, on ground like this, never adds up to an easier day.

The time working shows only an hour's difference, but this is where the maths stops telling the whole story. The last stretch under the gap is the most technical bit of the entire tour: loose rock, a faint path, cairns and nothing else to guide you. A group taking it carefully will lose a lot more than an hour there, and in fog, finding your way becomes the real challenge. Early in the season, snow covers the passage right into July.

Our rule is a simple one. Clear sky, snow gone, eight days already in the legs, and a group happy on scree: it's the finest day the Swiss side has to offer, glacier du Trient right there in front of you on the way down. Any doubt on one of those four counts, take Bovine instead, no regrets, and the alpage more than makes up for it.

• Distance :↔ 12.9 km
• Dénivelé positif :↗ 1185 m
• Dénivelé négatif :↘ 1341 m

The full comparison of both routes is in stage 8, Champex-Lac to Trient.

The Mont de la Saxe, 2,584 m, stage 5

Above the Rifugio Bertone, a path breaks off from the classic balcony route and climbs onto the ridge above the Italian Val Ferret. On our track, from the Bertone to the Bonatti, it adds 2.6 km and 465 metres of elevation gain, topping out at 2,554 m. Push on to the high point at the Tête de la Tronche (2,584 m) and you'll add roughly another hundred metres.

If we could only keep one of the eleven, it'd be this one. The ridge gives you a continuous view over the Grandes Jorasses, the Dent du Géant and the Aiguille Noire de Peuterey, all less than four kilometres off, with no blind spots and hardly a soul to share it with, since most walkers stick to the lower path. The classic Armina route is pretty and sheltered, sure, but it's not playing in the same league.

The price is a fair one, mind. Four hundred and sixty-five metres of climbing with nothing to break it up, first thing in the morning, on a ridge with no water and no shade, on day five of the tour. In strong wind or under grey skies, it loses its appeal fast and keeps every bit of its cost.

• Distance :↔ 9.8 km
• Dénivelé positif :↗ 676 m
• Dénivelé négatif :↘ 630 m

The full rundown of the day is in stage 5, Courmayeur to refuge Bonatti.

The refuge de Tré-la-Tête, 1,970 m, stage 2

This is the most lopsided variant of the lot, and it's worth reading closely. It replaces 3.6 km of valley floor between Les Contamines and the refuge de Nant-Borrant, a flat stretch that gains 276 metres without ever losing any. The variant, by contrast, climbs up to the refuge de Tré-la-Tête (1,970 m) before dropping back to Nant-Borrant: 555 extra metres of climbing, 4.1 km more, and close to three extra hours on your feet.

The gap looks brutal because the stretch it's replacing happens to be the easiest on the whole circuit. It's not that this variant is hard on its own terms, it's that the alternative is a nearly flat forest track, one of the few bits of the TMB you can walk without really trying.

What you gain is a balcony above the val Montjoie, looking across at the Dômes de Miage and the glacier de Tré-la-Tête, while the valley floor stays tucked under forest the whole way. The refuge itself is a grand stop, old-fashioned and well looked after.

What you lose is the day's only real chance to catch your breath. Stage 2 finishes at the col de la Croix du Bonhomme, 2,443 m, after a long climb. Tack on 555 metres and three hours before that climb, and a decent stage turns into a proper big day. In practice, this variant only really works if you split stage 2 in two and sleep at Nant-Borrant or la Balme.

• Distance :↔ 7.7 km
• Dénivelé positif :↗ 834 m
• Dénivelé négatif :↘ 537 m

The classic route through the val Montjoie is covered in stage 2, Les Contamines to Les Chapieux.

The col du Tricot, 2,120 m, stage 1

This is the priciest variant on the whole tour: 575 metres more climbing than via the col de Voza, for an extra 2.1 km and around two more hours on your feet. It's also the one people take most often.

From the col de Voza, the path runs below the hôtel de Bellevue, drops to the Himalayan-style footbridge slung above the torrent de Bionnassay, then climbs steeply through gravel up to the col du Tricot (2,120 m), face to face with the glacier de Bionnassay and the Dômes de Miage. From there it drops back down to the refuge de Miage before rejoining Les Contamines.

The real issue with the Tricot isn't how hard it is, it's when it falls in your day. Those two hours land on day one, when your pack's at its heaviest and your body hasn't found its legs yet. On a tight schedule, you'll be paying for that all week.

That's exactly why the planning matters more than fitness here. A 10-day TMB itinerary splits the first day in two and sleeps at Bionnassay, which makes the Tricot a comfortable outing right from the first morning. On a tighter tour, the same variant turns into a gamble.

• Distance :↔ 19.3 km
• Dénivelé positif :↗ 1541 m
• Dénivelé négatif :↘ 1363 m

Both first-day routes are compared in stage 1, Les Houches to Les Contamines.

When each variant opens up

The variants don't come into season along with the tour itself. A mid-June TMB is a lovely walk on the main route while half the high variants are still buried, and it's the question we get asked least, even though it decides everything for anyone setting off early.

The last three to clear are the col des Fours, the Fenêtre d'Arpette and the Mont-Fortin. Reckon on early July for the col des Fours, whose descent to the Ville des Glaciers faces north and holds its snow well after the pass itself has dried out. The same goes for the Fenêtre d'Arpette, where the scree under the gap keeps its snow longer than the rest of the valley, and where a steep patch over boulders is a far more serious business than one over open pasture. The Mont-Fortin, holding a long ridge above 2,500 m, really depends on the winter and needs judging case by case.

The rest can be taken as soon as the huts open for the season. The col du Tricot, the Mont de la Saxe and the Lac Blanc might carry the odd patch in June, but on ground you can still cross without bother. The Prarion, the ladder bypass and the Aiguillettes des Houches don't raise any seasonal questions at all.

One thing you won't see on any map: two of these variants are bone dry. The Mont de la Saxe ridge has no water between the Rifugio Bertone and the Bonatti, and the high stretch above the Lac Blanc is just as dry until you reach the Flégère. Two litres a head at the start isn't being overly careful, it's the bare minimum.

How we choose, in order

Out on the ground, the decision always follows the same order, and the view comes last of all.

Lodging first, because that's booked six months out and there's no fixing it later. Three variants change how the nights fall: the col des Fours skips Les Chapieux, the Mont-Fortin skips the Rifugio Elisabetta, and the Fenêtre d'Arpette means starting from Champex rather than somewhere in between. Those three get decided at booking time. Our roundup of Tour du Mont-Blanc mountain huts shows where everything sits.

Next, the morning weather, and above all when you expect to reach the high point. The col des Fours, the Mont-Fortin and the Fenêtre d'Arpette all run over open ground above 2,600 m. A storm forecast for early afternoon rules every one of them out, whatever shape the group's in.

Then come the legs, and here you factor in the next day too, not just the one ahead of you. A variant with 500 metres of climbing rarely costs you that evening, it costs you the next morning instead.

The view comes after all that. It only settles things between whatever's left standing, and there's nearly always something left.

One last habit that heads off more bad days than anything else: plan the route without the variants first, then add them in on the day when everything lines up. A short day can always be stretched on this circuit. A day built around your best possible form can't be shortened once you're already committed to it.

The other departures from the route, and what they're worth

The TMB has a few other departures from the main route that we've left out of the table, because they're a different sort of thing altogether.

The Aiguillette des Posettes needs a word of clarification, because it's often billed as a variant of stage 9 when it really isn't one, the TMB already runs the ridge: it drops to the col des Posettes around 2,010 m, climbs back over 2,150 m along the crest, then heads down towards Trè-le-Champ. The real alternative here is the low-level descent via Charamillon and Le Tour, which shortens the day by dropping below the lift network. It's also the descent most walkers end up pulled towards anyway.

Valley connections are a different matter entirely. The descent to Vallorcine rather than via Trè-le-Champ, the bottom of the Swiss Val Ferret by road, the exit through Le Tour and Montroc: these aren't mountain variants, they're fallback routes. They save you elevation gain on a day when the weather turns or an ankle starts complaining, which is exactly what they're for. Better to know they're there than discover them in the rain.

The refuge Robert Blanc area (2,750 m), above the Mottets, is another thing again. The col d'Enclave, the sentier Thomas Roques and the col des Bouquetins make up a high-route network that crosses the TMB without belonging to it: cabled sections, long days, proper high-altitude terrain. The Mont-Fortin already sits right on that edge, and we kept it in because it stays waymarked and technically straightforward, bar one demanding scree descent. Past that point, you're into separate hikes that want planning as such.

Mechanical shortcuts, finally, aren't variants either, but they change a trip a good deal: the tramway du Mont-Blanc, the Brévent cable car, the Checrouit gondola above Courmayeur, the Swiss postal buses. Their effect on the number of days is covered in our article on how many days the TMB takes.

Frequently asked questions about TMB variants

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