L'key takeaway: The UTMB distance changes from one edition to the next: always use the race page for the year you're targeting, not a rounded figure. Over such a distance, pace, sleep, and nutrition matter as much as your legs. Mandatory gear should be tested during training before race day.
The same ultra sometimes shows a different distance on two different pages, which is frustrating. You want to know how many kilometers to really expect for the Ultra-Trail du Mont-Blanc. In this article, we look at the official distance, what makes it change from one edition to the next, and what that means for your effort, time, and gear.
Table of contents
- How many kilometers is the Ultra-Trail du Mont-Blanc
- The distance changes from one edition to the next as the course shifts with the terrain
- Where the UTMB fits into the week of races around the mountain range
- The time limit sets the actual duration of the effort
- How to keep going through more than two days of racing
- Mandatory kit, from your running vest to your phone battery
- FAQ
How many kilometers is the Ultra-Trail du Mont-Blanc
L'UTMB 2026 covers 174 km and 9,700 m of elevation gain, completing a full loop of the massif through France, Italy, then Switzerland. The race starts on Friday, August 28 at 7:45 p.m. in Chamonix, where it also finishes. At the foot of Brévent, you can see runners walking up the slope without embarrassment, and that makes sense. To maintain your pace over such a distance, it helps to know how to adjust your trail running pace and to consult our guide to ultra-trail distances to understand where extreme effort really begins.
The 170 km and 10,000 m of elevation gain you often see are rounded figures, intended for presentation. They give you a sense of the race without stating the exact numbers. For a specific edition, use the figures on its race page, as the course may change to suit the terrain constraints. Building a race plan around a rounded figure is an unnecessary risk.
The distance changes from one edition to the next as the course shifts with the terrain
It's not a reading error: the numbers really do change. Comparing two race pages, we can see that the 2024 UTMB was 173.3 km, while the 2025 race was 174.2 km. The elevation gain follows the same pattern: 9,525 m in 2024 and 9,920 m in 2025, an increase of 395 m. The course is adjusted to suit the terrain constraints, so one edition is not the same as the next. For 2026, go by the official race page: 174 km and 9,700 m of elevation gain. Use the precise figures for training and strategy, never a rounded number from a race report. For your upper body over these distances, opt for lightweight-fiber trail T-shirts that dry quickly and don't weigh down your shoulders under your pack.
Where the UTMB fits into the week of races around the mountain range
UTMB week features several races of very different distances. Here's how they fit together, from shortest to longest.
The week's short-distance races
The week starts with accessible distances. L'ETC is 15 km with 1,200 m of elevation gain, starting from Courmayeur on Tuesday, August 25 at 2 p.m., with 4 hours 30 minutes to finish. Next comes the MCC, 40 km and 2,350 m of elevation gain, starting from Martigny-Combe on Monday, August 24, and the OCC, 60 km and 3,500 m, starting from Orsières on Thursday the 27th. Before your first long race, it's crucial to know what to eat before a trail run to avoid deficiencies: in Courmayeur, we've seen runners start on an empty stomach, and they pay for it on the climbs.
The week's long-distance races
The PTL goes much further: 300 km and 25,000 m of elevation gain, starting from Chamonix on Monday, August 24 at 8 a.m., with a maximum time of 151 hours. And there are no course markings on the ground: you need to know how to navigate, both on and off the trails. The UTMB course is marked. For an extraordinary ultra, you can also read our article on the Diagonale des Fous ultra-trail. Without a map and compass, it's best to stick to the UTMB. The CCC starts on the same day as the UTMB, from another town in the mountain range. Here's how they differ.
| Criterion | CCC | UTMB |
|---|---|---|
| Distance | 108 km | 174 km |
| Elevation gain | 6,200 m elevation gain | 9,700 m elevation gain |
| Start | Courmayeur, Friday, August 28 at 9 a.m. | Chamonix, Friday, August 28 at 7:45 p.m. |
| Maximum time | 28 h | 45 h 30 |
Two races in the same mountain range, but radically different experiences in terms of commitment and preparation.
The time limit sets the actual duration of the effort
The time limit is 45 h 30. This means you can't run at your usual long-run pace. You need to start conservatively, and that's where most runners go wrong. The cutoffs are listed on the course map for this year's edition. To learn how to maintain a steady pace, read our guide to managing your effort on a trail run, then set your pace according to this time limit.
The 2025 winner finishes in 19 h 18 min 58 s. The average finisher, meanwhile, takes 39 h 30 min, a gap of 5 h 6 min. At the nighttime aid station, you see runners sitting on a chair, eyes closed, setting off again without a word. Between 69 and 72% of finishers complete the race without sleeping. Train for an all-nighter before lining up: it’s a practical benchmark that few runners truly plan for.
How to keep going through more than two days of racing
A gel you’ve never tried before the start will come back to haunt your stomach around kilometer 80. Test your food and drink in training and find out what you digest well before race day. To build up to these long runs, check out our 100 km trail training guide. Anything you haven’t tried during training has no place in your bag on race day.
Over two days, you’ll eat and drink on the move. Start with a simple plan:
- Aim for 250 to 300 kcal per hour, including 40 to 80 g of carbohydrates.
- Drink 500 to 600 ml of water per hour, and adjust according to your plan, how much you sweat, and the weather.
- Bring enough to get you to the next aid station, because the UTMB is run semi-autonomously.
- Keep sleep in mind: in the 165 km ultras studied, runners slept for an average of 76 minutes. This is a benchmark, not an UTMB-specific rule.
Mandatory kit, from your running vest to your phone battery
The mandatory kit stays with you from the start to the finish, no exceptions. You may be subject to checks anywhere, and a missing item will cost you a penalty. Why so strict? If you spend a night outdoors in the rain, this kit becomes your shelter, and it must hold up while you wait for rescue. Test it in training: any gear you haven’t worn on a long outing shouldn’t come with you. A lightweight waterproof jacket is one of the essentials, and choosing the right model makes all the difference over 45 hours of effort.
To keep your soft flask and food within easy reach in your vest, see how to choose the right hydration pack volume. Also prepare your phone by following these three steps:
- Activate your phone’s international plan before you leave.
- Keep your phone charged, and never put it in airplane mode.
- If you expect to run for more than 15 hours, bring a power bank.
The UTMB distance changes from one edition to the next: the race details for the year in question are what matter. Check them before setting your plan. Rounded figures give you an idea of the race, but aren’t suitable for calculating your pace. Note the exact distance and elevation gain in your training plan, then build your long runs around them. For technical gear that meets the mandatory equipment requirements, explore men’s trail running jackets designed for the most demanding mountain conditions.
FAQ
How long does it take on average to finish the UTMB?
On average, UTMB finishers take 39 h 30 min, with a spread of 5 h 6 min. In practical terms, expect to race for more than a day and a half, and don’t base your plan on this average alone. The 2025 winner finished in 19 h 18 min 58 s, which illustrates the wide range of competitors’ abilities.
What is the standard UTMB entry fee?
The standard entry fee for the UTMB changes from one edition to the next. To find out the price, check the entry terms for the year you’re targeting before registering. Never rely on a price from an old race report: fees change regularly.
Do you need a UTMB Index to register for the UTMB?
Yes. You need a valid UTMB Index in the 100K or 100M category to register for the UTMB. To enter the Finals lottery, you also need at least one Running Stone. Check your index before paying your entry fee, not afterward.
How much elevation gain should you accumulate in training before entering the UTMB?
There is no universal amount of elevation gain to reach in training: it depends on your starting level and running history. Increase your elevation gain little by little, and have a coach or healthcare professional approve your plan before taking on a race of this distance.