23km du Mont-Blanc - Elevation Profile, Aid Stations and Cutoffs
23km du Mont-Blanc is a 23 km ultra-trail with around 1,680 m of elevation gain, starting in Chamonix, France. The overall cutoff is 6 hours 50 minutes. The highest point on the course is Planpraz at 2,051 m.
- Distance
- 23 km
Finishes 1,008 m higher than it starts
- Elevation
- +1,680 m -672 m
About 73 m of climb per km
- Highest point
- 2,051 m
Planpraz
Next edition Sat 26 Jun 2027 · 07:00
in about 9 months- Start
- Winner ~2h06 2h06 after the start
- Median finisher 2026 median 4h31 after the start
- Cutoff 6h50 after the start
Race details
Explore the 23km du Mont-Blanc course, kilometre by kilometre
Built from the organiser's course data, set to the 07:00 start.
- Map Interactive map
- Profile Elevation profile
- Checkpoints Checkpoints and cutoffs
- Weather Race-day weather
The biggest climb between checkpoints gains around 472 m from Bas du Plagnolet (km 15.37) to La Flegere (km 19.05). The steepest sustained section on the elevation profile averages about 17% over roughly 2 km around km 12. Crew access is allowed at Montroc (11.73 km) and La Flegere (19.05 km).
Data is approximate and courses change between editions - always verify against the official race guide.
Enter a goal finish time and see estimated arrivals vs checkpoint cutoffs.
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Elevation profile
Course math
Four numbers worked out from this course's distance, elevation and checkpoints.
TrailMath effort-km
43 effort-km
Below 50 effort-km the model quotes no reference time.
Distance + gain ÷ 100 + loss ÷ 200, beside ITRA's gain-only km-effort. Model TM1.0.
How TrailMath works →UTMB Index category
20K
39 km-effort (distance + gain ÷ 100). Calculated from the course figures, not an official classification.
Estimate your UTMB Index →Biggest climb section
+472 m
Bas du Plagnolet → La Flegere · km 15.4–19.1
The largest gain between two checkpoints, not one continuous climb.
Biggest descent section
−268 m
Montroc → Bas du Plagnolet · km 11.7–15.4
The largest loss between two checkpoints. ITRA's km-effort ignores descent; TrailMath counts it: 43 km-effort.
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23km du Mont-Blanc · 2026
Finish times, 2026 edition
1,771 runners finished. Half of them took longer than 4:31:02. That left the median finisher 2:18:46 inside the 6h50 cutoff.
Median finish
4:31:02
Half of the 1,771 finishers were still out there at this point.
2:18:46 in hand before the 6h50 cutoff
Average 4:25:51, 0:05:11 quicker than the median: a fast front pulls it down.
The start line
Men and women
Two medians on the same scale. The bars run from the start to the cutoff, so the gap between them is the gap in time.
Men
4:16:46
median finish; average 4:13:57
1,051 finishers, 59% of the field
Women
4:47:04
median finish; average 4:43:12
720 finishers, 41% of the field
0:30:18 separates the two medians, across 1,051 men and 720 women.
Finish time by age group
Every track runs from the start to the 6h50 cutoff, so the empty part of a bar is the time that group's median finisher still had. Men and women are drawn on the same scale.
| Age | Median finish | Median against the cutoff | Finishers |
|---|---|---|---|
| ES | 3:04:30 | 41 | |
| SE | 4:04:44 | 416 | |
| M0 | 4:06:02 | 166 | |
| M1 | 4:30:31 | 125 | |
| M2 | 4:22:27 | 84 | |
| M3 | 4:24:00 | 94 | |
| M4 | 4:47:17 | 62 | |
| M5 | 4:30:41 | 35 | |
| M6 | 5:02:54 | 21 | |
| M7 | 5:07:18 | 5 - small sample, read with care | |
| M8 | - | 2 - too few finishers to publish a time |
| Age | Median finish | Median against the cutoff | Finishers |
|---|---|---|---|
| ES | 4:24:51 | 31 | |
| SE | 4:38:41 | 389 | |
| M0 | 4:48:54 | 108 | |
| M1 | 4:55:48 | 65 | |
| M2 | 5:05:40 | 60 | |
| M3 | 5:11:59 | 38 | |
| M4 | 4:52:22 | 18 - small sample, read with care | |
| M5 | 5:22:25 | 8 - small sample, read with care | |
| M6 | 5:17:21 | 3 - small sample, read with care |
Full bar: 20 finishers or more. Tick alone: fewer than 20, too few for a median to say much. The shaded row is the biggest group.
Where the finishers came from
79% of the finishers came from France alone.
| Nation | Finishers | Share |
|---|---|---|
| France FR | 1,398 78.9% | |
| Belgium BE | 81 4.6% | |
| United Kingdom GB | 65 3.7% | |
| Switzerland CH | 33 1.9% | |
| Spain ES | 19 1.1% | |
| Germany DE | 18 1.0% | |
| Italy IT | 14 0.8% | |
| Norway NO | 13 0.7% | |
| Sweden SE | 11 0.6% | |
| United States US | 10 0.6% | |
| Netherlands NL | 9 0.5% | |
| Poland PL | 8 0.5% | |
| Argentina AR | 6 0.3% | |
| Canada CA | 6 0.3% | |
| Czechia CZ | 6 0.3% | |
| Denmark DK | 5 0.3% | |
| Ireland IE | 5 0.3% | |
| Portugal PT | 5 0.3% | |
| Brazil BR | 4 0.2% | |
| China CN | 4 0.2% | |
| Colombia CO | 4 0.2% | |
| Finland FI | 4 0.2% | |
| Greece GR | 4 0.2% | |
| Philippines PH | 4 0.2% | |
| Australia AU | 3 0.2% | |
| Algeria DZ | 3 0.2% | |
| Lithuania LT | 3 0.2% | |
| Curaçao AN | 2 0.1% | |
| Austria AT | 2 0.1% | |
| Ecuador EC | 2 0.1% | |
| Romania RO | 2 0.1% | |
| Thailand TH | 2 0.1% | |
| Estonia EE | 1 0.1% | |
| Croatia HR | 1 0.1% | |
| India IN | 1 0.1% | |
| Japan JP | 1 0.1% | |
| Cambodia KH | 1 0.1% | |
| Lebanon LB | 1 0.1% | |
| Luxembourg LU | 1 0.1% | |
| North Macedonia MK | 1 0.1% | |
| Mauritius MU | 1 0.1% | |
| Mexico MX | 1 0.1% | |
| New Zealand NZ | 1 0.1% | |
| Panama PA | 1 0.1% | |
| Serbia RS | 1 0.1% | |
| Ukraine UA | 1 0.1% | |
| Uruguay UY | 1 0.1% | |
| South Africa ZA | 1 0.1% | |
| 38 other nations 28 other nations 18 other nations 8 other nations | 109 6.2% 51 2.9% 20 1.1% 8 0.5% |
Showing 20 of 48 nations. Showing 30 of 48 nations. Showing 40 of 48 nations. Showing 48 of 48 nations.
Bar length is against the largest nation. The smallest counts are drawn at a minimum visible width, so their bars are not to scale.
How these numbers were computed
These are times for runners who finished. They exclude everyone who started and did not, so they describe how long finishing took, not how long the race takes. Bands with only a handful of finishers move a lot from one edition to the next.
We plot the median, not the average. A handful of very quick runners drags the average well below the time half the field actually beat, so the median is the honest number to plan against.
Nationality here shows who travels to this race, not who runs it best. That alone is why a host nation tops almost every list.
Computed from the full official results, verified September 29, 2026 - Official results
Ask the course
Ask 23km du Mont-Blanc anything about climbs, pacing, crew or cutoffs.
Answers come from this course's data, your plan and your training.
Which climb should I respect most?
Bas du Plagnolet to La Flegere: +472 m over 3.7 km, from km 15.37. Hike the steep sections at an effort you could hold for hours - the race is decided after this climb, not on it.
Where can my crew meet me?
Montroc, km 11.73 - the first of 2 crew points. The next is La Flegere, km 19.05. Have them bring warm layers: the course tops out at 2,051 m, in June.
Is 4h a realistic finish for me?
4h would put you in the faster half of 2026 finishers - the median was 4:31:02. It means holding 10:26/km overall.
The Coach answers that once it can see your training.
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Example answer
Your long runs peak at 5 km, so the plan builds to 4-hour long runs. Cutoff buffer at Montroc: 1h36.
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Aid stations and checkpoints
| Checkpoint | Km | Cumulative gain (m) | Cumulative loss (m) | Cutoff | Crew | Drop bag |
|---|---|---|---|---|---|---|
| Start - Chamonix | 0 | 0 | 0 | - | - | - |
| Le Lavancher | 5.26 | 202 | 45 | - | No | No |
| Montroc | 11.73 | 578 | 255 | Sat 10:20 | Yes | No |
| Bas du Plagnolet | 15.37 | 923 | 523 | - | No | No |
| La Flegere | 19.05 | 1,395 | 551 | Sat 12:20 | Yes | No |
| Planpraz (Finish) | 23 | 1,680 | 672 | Sat 13:50 | Yes | No |
Data is approximate and courses change between editions - always verify against the official race guide. Source: official race guide, verified September 29, 2026 - Official race website
FAQ
How much elevation gain does 23km du Mont-Blanc have?
23km du Mont-Blanc has around 1,680 m of cumulative elevation gain and 672 m of loss over 23 km.
What is the cutoff time for 23km du Mont-Blanc?
The overall 23km du Mont-Blanc cutoff is 6 hours 50 minutes, with intermediate time barriers at major checkpoints. Winning times are typically around 2 hours.
How long is 23km du Mont-Blanc?
23km du Mont-Blanc covers approximately 23 km, starting in Chamonix, France.
What is the highest point of 23km du Mont-Blanc?
The highest point of 23km du Mont-Blanc is Planpraz at 2,051 m.
How many aid stations does 23km du Mont-Blanc have and which allow crew?
The checkpoint table lists 4 major aid points between the start and the finish. Crew access is allowed at Montroc (11.73 km) and La Flegere (19.05 km).
Training for this race?
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