The UTMB Ultra-Trail du Mont-Blanc is the most famous trail race on the planet. 171 km and 10,040 m D+ in a full loop of Mont Blanc, crossing France, Italy and Switzerland. If trail running were an Olympic sport, the UTMB would be the gold medal.
The numbers
| Metric | Value |
|---|---|
| Distance | 171 km |
| Elevation gain (D+) | 10,040 m |
| Highest point | 2,583 m |
| Countries | France, Italy, Switzerland |
| Start and finish | Chamonix (France) |
| Official cut-off | 46 hr 30 min |
The climbs that define the race
KM 18 — Col de Montets (1,461 m)
The first big climb, and it comes very early. Plenty of runners go out far too hard here and pay for it later on.
KM 65 — Mont Blanc du Tacul segment
The most iconic stretch in the Alps. The views are extraordinary, but you are exposed to the wind and to cold temperatures even in August.
KM 110 — Col des Pyramides Calcaires (2,583 m)
The high point of the UTMB. It arrives after more than 24 hours on your feet, and the thin air starts to bite.
KM 150 — La Flégère
The last big climb, and the hardest one mentally: you can see Chamonix below you, but there are still 20 km to go.
Reference times (2024-2025)
| Level | Estimated time |
|---|---|
| Elite (front of the race) | 19 hr – 23 hr |
| Advanced | 28 hr – 36 hr |
| Amateur | 36 hr – 44 hr |
| Official cut-off | 46 hr 30 min |
Fuelling strategy for 28-46 hours
- Hours 0-8: adrenaline. 250 kcal per hour.
- Hours 8-20: peak absorption. 350-400 kcal per hour.
- Hours 20-32: night falls and sleep deprivation kicks in. 250 kcal per hour.
- Hours 32-46: survival mode. Whatever you can stomach.
Mandatory kit
- Hooded down jacket.
- Waterproof trousers.
- Head torch with a spare.
- Survival blanket.
- Whistle.
- Basic first-aid kit.
Who should be running the UTMB?
- You have finished two or more ultras of 100 km or longer.
- You have run high in the mountains through the night.
- You can handle prolonged effort on very little sleep.
The bottom line
The UTMB is trail running's pilgrimage. It is not the most technical race on the circuit (that is the TDS), nor the one with the densest climbing (Transvulcania), but it is the most complete experience: 170 km, three countries, two nights and the birthplace of the sport.