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

On the Tour du Mont-Blanc, variants often get judged with the wrong unit of measurement. People usually ask how many kilometers a variant adds, when on this route distance predicts almost nothing. Measuring all eleven tracks one by one, three of them turn 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 cost practically nothing in climbing either. The third gains 425 meters more and remains the hardest day of the tour.

At Altimood, we lead groups on this route and record the tracks season after season. This article compares all eleven usable variants to the route they replace, with the real difference in distance, elevation gain and walking time. Each one has its own downloadable GPX track.

One clarification before the numbers: "worth the detour" isn't a data point, it's an opinion. Ours depends on the morning weather, the group's condition and what we've already seen on previous days. The measurements, though, don't move, and that's what lets us discuss the rest on solid ground.

The 11 variants compared to the classic route

Each row compares the variant to the exact section it replaces, with identical start and end points on both sides. The differences are measured on our own tracks, with the same smoothing used for the elevation profiles shown further down. Time is calculated for a steady hiker carrying a trekking pack, roughly 370 m of climbing per hour.

The ranking runs by elevation cost, from cheapest to priciest, not by distance. That's the figure that really matters on a multi-day trek: kilometers can be made up, but meters of climbing pile up from one day to the next.

So read both columns together, never separately. The Fenêtre d'Arpette makes the point best: 3.3 km shorter, yet the hardest day of the circuit, because it climbs 425 meters more over a scree slope. Conversely, the col des Fours is the only variant negative in both columns, and the Petit Col Ferret isn't far behind, its extra thirty-five meters of climbing thin enough to be rounding error. Those are the two bargains of the tour.

The table also settles a question that comes up often: the tour's highest point. On the main route, the TMB tops out at the Grand Col Ferret, 2,537 m. With the variants, the highest ground actually walked on any one itinerary is on the Mont-Fortin traverse, around 2,730 m, on the mountain's flank rather than its summit. Higher still, but as an out-and-back rather than on the tour itself, the Tête Nord des Fours (2,756 m) is reached in twenty minutes from the col des Fours: it's the highest point your feet can actually stand on along the whole route. And two passes share the altitude of 2,665 m, the col des Fours and the Fenêtre d'Arpette, one in France and the other in Switzerland. The "high point" column gives the official altitude of the place crossed, which our tracks reach within a few meters, except where the path deliberately passes below the summit.

What a variant really costs

The classic TMB route runs about 170 km for around 10,000 m of elevation gain. Stringing together the six high-altitude variants, col du Tricot, col des Fours, Mont-Fortin, Mont de la Saxe, Fenêtre d'Arpette and Lac Blanc, distance barely moves while elevation gain picks up about 1,800 m.

That's the whole point. On this route, a variant isn't paid for in kilometers, it's paid for in climbing. High-altitude paths cut straight over the passes while the main route skirts around lower down, so they end up covering a little less distance but a lot more height. Across the whole tour, the distance gap adds up to a few hundred meters, which is to say nothing: it's below what any track measurement can even distinguish.

The 1,800 m of climbing, though, you feel. It amounts to nearly 20% more effort across the whole route, and it stretches the days even when the map shows the same length. A tour with all the variants is noticeably harder than one without, full stop. What the measurement gives you is simply knowing where to look: the elevation column, never the kilometer one.

The trade-off, then, comes down to your legs, your schedule and the next day. To see what those 1,800 meters do to your itinerary, our TMB duration calculator factors in all eleven variants from this article and recalculates the nights accordingly, taking into account which lodgings each one skips.

The variants that cost almost nothing

Four variants can be taken without reorganizing the day. They add less than 100 meters of climbing, and one of them actually removes some.

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

It's the only variant on the whole tour that's both shorter and less climbing than the route it replaces: 3.8 km and 40 meters of elevation gain less. The reason comes down to geography. From the refuge de la Croix du Bonhomme, the classic path drops 900 meters to Les Chapieux, down in the valley floor, before climbing back up 320 meters to Les Mottets. The variant, instead, keeps climbing another 190 meters to the col des Fours, then drops straight into the vallée des Glaciers and rejoins the TMB further down.

So you walk less to get higher. The view from the pass, at 2,665 m, opens onto the Écrins to the south and the Mont-Blanc massif to the north. For anyone with time and clear skies, an easy shoulder extends due north from the pass to the Tête Nord des Fours (2,756 m) in about twenty minutes, the best viewpoint in the area.

What the variant really costs is the night at Les Chapieux. The hamlet is a resupply point and one of the few places in this area where you can sleep, and the col des Fours bypasses it entirely. It's a scheduling choice as much as a route choice, one to make when booking, not on the morning itself.

The other condition is the weather. At 2,665 m on an exposed shoulder, a storm is something you simply have to ride out. The snow patch on the descent to the Ville des Glaciers often holds until early July, and that steep descent is what eats up, on the ground, the theoretical 55-minute head start. Expect roughly the same time as via Les Chapieux, just with different scenery.

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

The full breakdown of the day and the comparison with the classic descent are in stage 2, Les Contamines to Les Chapieux.

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

This is the best bargain of the tour, and by far the least known. Between the Rifugio Elena and La Fouly, the Petit Col Ferret (2,490 m) is 3.7 km shorter than the classic passage via the Grand Col Ferret, for thirty-five extra meters of climbing. Thirty-five meters is measurement noise. So that's nearly four kilometers and three-quarters of an hour handed to you for free.

The explanation lies in the descent, not the climb. The classic pass drops onto the alpage de La Peule and follows the whole upper Val Ferret on the Swiss side before reaching La Fouly. The Petit Col Ferret, forty meters lower and one kilometer further west, drops more directly into the valley. On the track, it passes two and a half kilometers from La Peule, never seeing it.

That's also what makes it less of a no-brainer than it looks. The Swiss side of the Petit Col Ferret is steeper and far less used, the path is fainter, and the alpage de La Peule you skip is one of the good stops on the Swiss side, with its cheeses and terrace. You save time by giving up a break that plenty of walkers rank among their favorite memories.

Our take: it's worth it on a day when time is tight, or when the weather is closing in and you need to be down early. On a normal day, La Peule is worth walking the four kilometers for.

• 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 described in stage 6, refuge Bonatti to La Fouly.

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

Ninety extra meters of climbing and four hundred extra meters of distance, for an almost continuous ridge walk above the Val Veny. On paper, it's the best bargain of the tour.

On the ground, it's the most committing variant on the list, and the table doesn't show that. It starts right after the col de la Seigne, follows the col des Chavannes (2,598 m), the flank of the Mont-Fortin, then the col de Youla (2,661 m), and descends to the Col Chécrouit. Almost the whole thing runs above 2,500 m, far from anything, with no bail-out option once you're committed. Our track tops out at 2,730 m.

It's more of a high-route traverse than a TMB variant. We only take this on with groups already seasoned at altitude, in stable weather and with a comfortable time margin. The real cost isn't in the 90 meters, it's in the commitment.

This variant also bypasses the Rifugio Elisabetta, the natural lodging for this section. So it changes 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 described in stage 4, Rifugio Elisabetta to Courmayeur.

The ladder bypass, stage 10

This isn't a scenery variant, it's a solution. The eleven metal ladders at Trè-le-Champ put off a fair number of hikers, and a waymarked path avoids them via the col des Montets. It adds 2.1 km and only 85 meters of elevation gain.

Its real value lies elsewhere: measured on the track, this bypass rejoins the TMB at the Tête-aux-Vents (2,132 m), which is upstream of the Lac Blanc turnoff. So skipping the ladders doesn't cost you the lake, contrary to what the map suggests at first glance.

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

The circuit's other exposed passages and their bypasses are detailed in our article on the Tour du Mont-Blanc for hikers afraid of heights.

The variants that cost an hour or two

Three variants fit within a morning's head start. They're decided on the day, with a look at the sky.

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

On the last day, instead of dropping straight from Bellachat to Les Houches, you extend along the Aiguillettes des Houches ridge before heading down. The variant adds 3.4 km and 180 meters of climbing for about 1h15.

It's the least taken of the eleven, and that makes sense: on day eleven, you've got a train to catch, tired legs and a tour already wrapped up in your head. It's mainly worth it if you're finishing early and want to stretch out the last descent instead of just enduring it. This side is also noticeably quieter than the direct path.

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

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

The Lac Blanc, 2,352 m, stage 10

The most photographed detour in the Alps costs 1.7 km and 285 meters of climbing from the Tête-aux-Vents, roughly 1h30 round trip. The lake's milky color comes from rock particles ground down by glacial abrasion, and the reflection of the Drus in the first pool is the image everyone knows.

It's the tour's most weather-dependent variant. Under clear skies, it's easily worth the hour and a half. Under a low ceiling, all that's left is a gray lake and a climb for nothing, and the energy is better saved. It's also the only one on the list you can decide at the very last second, since the turnoff is at the cairn on the Tête-aux-Vents, with the sky right there in front of you.

Since stage 10 is the shortest on the circuit, this detour almost never causes a scheduling problem.

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

The lake also makes a great day hike outside the TMB: see our article on Lac Blanc from Chamonix.

The Prarion, 1,967 m, stage 1

Starting 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 summit of the Prarion (1,967 m), before dropping back down to the col de Voza. The variant adds 4.6 km and 300 meters of climbing, making it the longest add-on on the list, though not the hardest.

Its appeal is as much social as scenic. Day one of the TMB is when you cross paths with the most people, since everyone leaves Les Houches around the same time. The Prarion side sits away from that flow and away from the lifts, it climbs through shaded forest, and it opens onto a 360-degree view taking in the Mont-Blanc massif, the Chamonix valley and the Aravis.

It's the option worth knowing about if you're setting off in peak season and the first day's crowds worry you.

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

The variants that cost half a day

The last four come at a price. They require having planned the day accordingly, not just deciding over breakfast.

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

This is the big dilemma of the Swiss side. Between Champex-Lac and Trient, the Fenêtre d'Arpette is 3.3 km shorter than the Bovine route, and that's the figure that surprises everyone. It doesn't make the day any easier for it: it climbs 425 meters more, concentrated on a scree slope, and remains the most demanding day on the circuit. Walking less distance while climbing more, on terrain like this, never translates into a lighter day.

The time calculation shows only an hour's difference, but this is where the model hits its limit. The final stretch below the gap is the most technical passage on the tour: loose blocks, a faint path, cairns as the only waymarking. A group moving cautiously loses far more than an hour there, and in fog, route-finding becomes the real issue. Early in the season, snow patches cover the passage into July.

Our rule is simple. Clear skies, snow melted out, eight days of walking already in the legs, and a group comfortable on scree: it's the finest day on the Swiss side, with the glacier du Trient facing you on the way down. Any doubt on one of those four points: take Bovine, no regrets, and the alpage is worth the detour on its own.

• 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 leaves the classic balcony route and climbs onto the ridge overlooking the Italian Val Ferret. On our track, measured from the Bertone to the Bonatti, it adds 2.6 km and 465 meters of elevation gain and tops out at 2,554 m. Pushing on to the high point of the Tête de la Tronche (2,584 m) adds roughly another hundred meters.

If we had to keep just one of the eleven, this would be it. The ridge unrolls a continuous panorama over the Grandes Jorasses, the Dent du Géant and the Aiguille Noire de Peuterey, less than four kilometers away, with no blind spots and hardly anyone to share it with: the vast majority of hikers stay on the lower path. The classic route via Armina is pretty and sheltered, but it isn't playing in the same league.

The price to pay is steep, literally. Four hundred sixty-five meters of unbroken climbing 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 an overcast sky, it loses all its appeal and keeps every bit of its cost.

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

The full breakdown 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 in the table, and it needs to be read carefully. It replaces 3.6 km of valley floor between Les Contamines and the refuge de Nant-Borrant, a flat section that climbs 276 meters without ever losing height. The variant, instead, climbs to the refuge de Tré-la-Tête (1,970 m) before dropping back down to Nant-Borrant: 555 meters more climbing, 4.1 km more, and nearly three extra hours of walking.

The ratio looks brutal because the section it replaces is the easiest on the circuit. It's not that the variant is hard in absolute terms, it's that the alternative is an almost flat forest track, one of the rare stretches on the TMB where you walk without effort.

What you gain is a balcony above the val Montjoie, facing the Dômes de Miage and the glacier de Tré-la-Tête, whereas the valley floor stays under forest cover. The refuge itself is a lovely stop, old and well kept.

What you lose is the day's only stretch of recovery. Stage 2 ends at the col de la Croix du Bonhomme, at 2,443 m, after a long climb. Adding 555 meters and three hours ahead of that climb turns a reasonable stage into a genuinely huge day. In practice, this variant only really works if you split stage 2 in two and sleep at Nant-Borrant or at la Balme.

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

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

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

This is the priciest variant on the tour: 575 meters more elevation gain than via the col de Voza, for an extra 2.1 km and roughly two more hours of walking. It's also the one most often taken.

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

The real problem with the Tricot isn't its difficulty, it's its place in the schedule. Those two hours land on day one, when the pack is at its heaviest and the body hasn't absorbed anything yet. On a tight itinerary, you keep paying for them all week.

That's why scheduling matters more than leg strength here. A 10-day TMB itinerary splits the first day in two and sleeps at Bionnassay, which makes the Tricot comfortable from the very first morning. On a tight tour, the same variant becomes 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 open up at the same time as the tour itself. A mid-June TMB walks perfectly well on the main route while half the high variants are still under snow, and it's the question we get asked least even though it decides everything for an early departure.

The last three to clear are the col des Fours, the Fenêtre d'Arpette and the Mont-Fortin. Expect early July for the col des Fours, whose descent to the Ville des Glaciers faces north and holds snow well after the pass itself is dry. Expect the same window for the Fenêtre d'Arpette, where the scree below the gap stays under snow longer than the rest of the valley, and where a steep snow patch over boulders is a far more serious matter than one over an alpage. The Mont-Fortin, which holds a long ridge above 2,500 m, has to be judged case by case depending on the winter.

The others can be taken as soon as the huts open. The col du Tricot, the Mont de la Saxe and the Lac Blanc can hold residual patches in June, but on terrain that's still passable. The Prarion, the ladder bypass and the Aiguillettes des Houches raise no seasonal question at all.

One thing no map shows: two of these variants are dry. The Mont de la Saxe ridge has no water source between the Rifugio Bertone and the Bonatti, and the high section above the Lac Blanc has none either until the Flégère. Two liters per person at the start isn't just caution, it's the bare minimum.

How we choose, in order

On the ground, the trade-off always follows the same order, and the view comes last.

First comes lodging, because it's booked six months ahead and can't be fixed later. Three variants change how the nights are split: the col des Fours skips Les Chapieux, the Mont-Fortin skips the Rifugio Elisabetta, and the Fenêtre d'Arpette forces you to start from Champex rather than an intermediate point. Those three get decided at booking time. Our roundup of Tour du Mont-Blanc mountain huts maps out the addresses involved.

Next comes the morning weather, and above all the expected arrival time at the high point. The col des Fours, the Mont-Fortin and the Fenêtre d'Arpette all run over exposed terrain above 2,600 m. A storm forecast for early afternoon rules out all three, whatever shape the group is in.

Then comes the state of your legs, factoring in the following day and not just the one at hand. A variant with 500 meters of climbing rarely costs you that evening: it costs you the next morning.

The view comes after that. It only tips the balance between whatever options are left, and there are almost always some left.

One last habit, the one that avoids the most bad days: plan the itinerary without the variants, then add them on the day when everything lines up. A short day can be stretched at will on this circuit. A day built around your best-case scenario can't be shortened once you're already committed.

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

The TMB has other departures from the main route that we didn't include in the table because they don't follow the same logic.

The Aiguillette des Posettes deserves a clarification, because it's often presented as a variant of stage 9 when it isn't one, the TMB already runs along the ridge: it drops to the col des Posettes around 2,010 m, climbs back above 2,150 m along the crest, then heads down to Trè-le-Champ. What does exist here as a genuine alternative is the low-level descent via Charamillon and Le Tour, which shortens the day by passing below the lifts. It's also the descent most hikers end up drawn into anyway.

Valley connections are a different animal. The descent to Vallorcine instead of via Trè-le-Champ, the bottom of the Swiss Val Ferret by road, the exit via Le Tour and Montroc: these aren't mountain variants, they're fallback options. They save elevation gain on a day when the weather turns or an ankle starts complaining, and that's exactly what they're there for. Better to keep them in mind than to discover them in the rain.

The refuge Robert Blanc area (2,750 m), above the Mottets, is another matter altogether. The col d'Enclave, the sentier Thomas Roques and the col des Bouquetins form a high-route network that crosses paths with the TMB without being part of it: cabled sections, long days, high-altitude terrain. The Mont-Fortin already sits on that borderline, and we kept it because it stays waymarked and technically straightforward apart from a demanding scree descent. Beyond that, these are separate hikes, and should be planned as such.

Mechanical shortcuts, lastly, aren't variants but they do change a trip significantly: 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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