Chamonix, FR · August 2026
UTMB Mont-Blanc
UTMB Mont-Blanc pacing strategy with effort-based splits, nutrition timing, and course-specific risk notes for the 174 km ultra.
- Distance
- 174.00 km
- Elevation gain
- 11391 m
- Typical temp
- 13–24 °C
- Cutoff
- 46:30:00
The short version
A brutal course
- Big climbing day — 11391 m up. Pace the ascents on effort, not the clock.
- Quad-pounding descent (11544 m down) — control the early downhills or pay for it late.
- Low sun in your eyes around km 4–92 — bring a cap or shades.
Next edition
28 August 2026
Typical race-day conditions
13–24 °C
We lock the real forecast into your plan in race week.
Course difficulty
BrutalDriven by 11391 m of climbing, altitude up to 2571 m, 11544 m of quad-pounding descent. Harder than Ultra-trail Cape Town 100 Miler (10.0), easier than Western States 100 (10.0) — tougher than 98% of the races we cover.
Race data quality
Medium confidence
Auto-generated from GPS route + elevation data
Course distance, climate, and broad course features are suitable for pacing previews. Elevation profiles and aid-station details are approximate and should be checked against the official race packet before race day.
Elevation profile
Route-derived (GPX + DEM)
Paid strategy guardrail
Official race packet remains source of truth
- Open-Meteo historical climate archive (2022–2024)
Step 1 · Free preview
See the course-adjusted plan first
Enter one recent result. The preview returns course cost, first splits, and fuel target from the deterministic engine and the current course data model.
VDOT
49.1
Estimate
21:12:13
Course cost
+460:34
Fuel target
60 g/h
60 g/h needs a trained gut — practise it in training, never try new fuelling on race day. Your full plan tunes this to your experience.
First 5 km preview
full race locked
- km 15:00
- km 25:02
- km 35:10
- km 44:56
- km 55:00
First race free · then €7 Race Pass · no monthly subscription
Uses an approximate course model; verify final logistics against the official race packet.
Step 2 · Your full UTMB Mont-Blanc plan
The preview shows the shape. The plan races it for you.
Course preview
Free
what you see now
- Difficulty score & course data
- Course-cost & toughest km
- Your first full plan free, ever
Race Pass
€7
one-time, this race
- Every km split, weather-adjusted
- Nutrition & fluid timeline
- Heat, wind & sun race tactics
- Danger zones + watch file (GPX)
- Race-week forecast & reminders
Annual
€19
per year, every race
- Everything in Race Pass
- Unlimited races, all year
- Re-plan as your fitness changes
No subscription required — one race is a one-off €7. See a full sample plan →
Continue with approximate course data →Course elevation
11391 m total gain · 11544 m loss · max 2571 m, min 810 m.
Fly the course
At Tour du Mont-Blanc loopSun & shade
Sun in your eyes
28 km
Sun on your back
16 km
Side / overhead
49 km
Expect low sun roughly in your eyes around km 4–92 — pack a peaked cap or shades; low glare hides kerbs and potholes. From km 123 the sun sits high overhead — peak UV and radiant heat, so keep sunscreen on and run the shaded side of the road where you can.
Approximate — solar position from the route geometry and a 17:45:00 start (timezone estimated from longitude), for a mid-pack finishing time.
Signature sections
Tour du Mont-Blanc loop · km 0–174
Long alpine climbs, technical descents, night running, and altitude exposure around the Mont-Blanc massif.
Aid stations
11 stations on course — plan your fueling around them.
Race overview
UTMB Mont-Blanc is the reference 100-mile mountain ultra: roughly 174 km around the Mont-Blanc massif with close to 10 000 m of climbing. A useful plan has to manage effort caps on long climbs, conservative descending, night fueling, and weather volatility. The current TrainingFlow model treats it as a course-specific effort plan with approximate vertical distribution until detailed course files are imported.
How hard is this course?
Reference table — how the UTMB Mont-Blanc compares to a flat sea-level course for four typical fitness levels. Computed from the route profile, mean course altitude, and typical race-week climate (19 °C / 65 % humidity). Your personal strategy uses your VDOT, per-km splits, nutrition timing, and the typical climate baseline for this static sample; paid strategies use Open-Meteo when a verified race date is inside the forecast window.
| Runner | Flat-course finish | UTMB Mont-Blanc finish | Course cost | Adjusted pace |
|---|---|---|---|---|
| Beginner (VDOT 35) | 17:43:36 | 27:47:08 | +56.7% | 6:30/km |
| Intermediate (VDOT 45) | 14:30:13 | 22:44:01 | +56.7% | 5:19/km |
| Trained (VDOT 50) | 13:19:22 | 20:52:57 | +56.7% | 4:53/km |
| Competitive (VDOT 60) | 11:29:41 | 18:01:02 | +56.7% | 4:13/km |
Reference nutrition
For a 70 kg runner finishing in 20:52:57 at 19 °C. Adjust to your weight and tolerance — these are ISSN-window targets, not prescriptions.
- Carbs / hour
- 60 g
- Total carbs
- 1253 g
- Fluid / hour
- 665 ml
- Sodium / hour
- 500 mg
FAQ
How should I pace UTMB Mont-Blanc?
Treat the preview as an effort plan, not a fixed road-marathon pace table. The course model includes 9900 m of climbing, so climbs, descents, heat, and aid-station timing matter more than average pace.
How reliable is the current course data?
Official headline distance and vertical gain are suitable for preview. The per-km elevation profile is approximate and must be upgraded with official GPX for high-confidence paid strategies.
Get your personalized strategy
The numbers above are samples. Sign up free and get the full UTMB Mont-Blanc strategy from your VDOT, the current course model, Open-Meteo race-week forecast when available, and your nutrition preferences.
First race free · €7 per additional race · €19/yr for unlimited
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New to trail and ultra pacing? Start with our trail and ultra pacing guide or run the VDOT calculator.