Last updated September 11, 2026
Mountain Difficulty Ratings: YDS, Alpine, UIAA & French Grades
A 5.7, UIAA V, French 4c and Alpine AD do not all mean the same thing. Some grades describe one hard rock move. Others describe the seriousness of an entire mountain route. This guide shows what each system measures, where approximate conversions are useful, and where conversion becomes misleading.
First identify what the grade is actually grading.
YDS 5.x, UIAA and French free-climbing grades primarily describe technical rock difficulty and can be approximately cross-referenced. French adjectival Alpine grades such as PD, AD and D describe the overall seriousness of an alpine route. Commitment grades describe time and commitment. Ice and mixed grades describe their own media. None should be treated as a complete mountain-risk score.
- YDS Class 1-4: hiking through scrambling and exposed simple climbing.
- YDS 5.x: technical rock climbing.
- UIAA I-XII+: technical rock movement.
- French 1-9: free-climbing difficulty.
- Alpine F-ED: overall route seriousness.
- NCCS I-VII: commitment and duration.
- WI / M: ice and mixed technical difficulty.
There is no universal one-number mountain difficulty scale.
A route can be technically easy but physically enormous, technically difficult but short, or moderate on rock yet extremely serious because of altitude, weather, rockfall, avalanche hazard or retreat. Always read the notation together with the route description.
Different Grades Answer Different Questions
Before comparing two numbers, determine whether both numbers describe the same type of difficulty.
Yosemite Decimal System
Classes 1 through 4 describe increasingly involved hiking, scrambling and exposed simple climbing. Class 5 is technical rock climbing and is subdivided into decimal grades.
UIAA Rock Grade
Roman numerals describe technical rock-climbing difficulty. Plus and minus modifiers refine the grade. The scale is open-ended.
French Free-Climbing Grade
Arabic numbers and letters such as 4c, 5c, 6a and 7a describe technical free-climbing difficulty. This is not the same system as the French adjectival Alpine grade.
French Adjectival Alpine
F, PD, AD, D, TD and ED describe the overall seriousness of an alpine route rather than only the hardest move.
NCCS Grade
Roman numerals such as Grade II, III or IV describe the duration and commitment of the technical climbing rather than its hardest individual move.
Ice and Mixed Grades
WI grades describe water-ice technical difficulty. M grades describe mixed climbing. These again answer a different question from an overall Alpine grade.
Think in layers.
A useful European alpine description might contain an overall Alpine grade plus a UIAA rock grade. A North American route may contain a YDS technical grade plus an NCCS commitment grade. Neither number makes the other redundant.
YDS, French Rock and UIAA Grade Translator
The table below follows the UIAA’s published comparison framework. It is useful for orientation, not mathematical conversion. Regional grading traditions and individual routes can differ.
| YDS | Approx. French rock | Approx. UIAA | How to read it |
|---|---|---|---|
| 5.2 | 1 | I | Very easy technical rock / scrambling boundary. |
| 5.3 | 2 | II | Easy rock climbing with abundant holds. |
| 5.4 | 3 | III | Easy fifth-class / straightforward technical climbing. |
| 5.5 | 4a | IV | More deliberate technical movement. |
| 5.6 | 4b | IV+ | Easy-to-moderate technical rock. |
| 5.7 | 4c | V | Moderate free climbing requiring reliable technique. |
| 5.8 | 5a | V+ | More sustained technical movement. |
| 5.9 | 5b | VI- | Technical rock where efficiency becomes increasingly important. |
| 5.10a | 5c | VI | Beginning of the YDS 5.10 range. |
| 5.10b | 6a | VI+ | Intermediate technical free climbing. |
| 5.10c | 6a+ | VII- | Stronger technical movement and smaller margins. |
| 5.10d | 6b | VII | Sustained intermediate-to-advanced free climbing. |
| 5.11a | 6b+ | VII+ | Advanced technical rock. |
Do not put AD, D or TD into this table.
Those are overall Alpine grades. An AD route might contain easy scrambling, UIAA III rock, snow, ice or some combination of them. The AD tells you about the complete alpine route; the UIAA or French rock grade tells you about the technical rock.
YDS Classes 1 Through 5
The transition from hiking to scrambling to climbing is gradual. Exposure and consequence can become serious before Class 5 begins.
Hiking
Walking on a trail or straightforward terrain without requiring the hands for upward movement.
Simple Scrambling
Rougher terrain with occasional hand use and off-trail movement.
Hands-On Scrambling
Hands are regularly required. Exposure can be substantial and a rope may be carried even though many parties climb unroped.
Exposed Simple Climbing
More technical and exposed terrain. A rope is often used because a fall can have severe or fatal consequences.
Technical Rock Climbing
Rope, belaying and protection define the technical climbing system. The class is then subdivided into decimal grades such as 5.4, 5.8 and 5.10a.
Class Is Not Consequence
A Class 3 route can still involve extreme exposure, falling rock, altitude, storms and difficult retreat.
Longs Peak is the useful example.
The Keyhole Route is commonly described in U.S. route literature as Class 3, but Rocky Mountain National Park emphasizes that it is a climb rather than a normal hike: exposed scrambling, narrow ledges, loose rock and terrain where an unroped fall may be fatal. The number alone does not communicate that consequence.
What F, PD, AD, D, TD and ED Mean
These are global route assessments. Think “How serious is the entire alpine objective?” rather than “How hard is the single hardest move?”
| Grade | French term | General interpretation | What can change the experience |
|---|---|---|---|
| F | Facile | Easy alpine terrain by mountaineering standards. | Glacier condition, snow, altitude and weather still matter. |
| PD | Peu difficile | Somewhat difficult; more involved snow, glacier or rock terrain. | Crevasses, steeper snow and route-finding can increase seriousness. |
| AD | Assez difficile | Fairly difficult alpine climbing requiring established technique and efficiency. | Length, exposure, mixed terrain and descent begin to matter greatly. |
| D | Difficile | Difficult and sustained alpine terrain with meaningful commitment. | Retreat, weather and speed become major safety variables. |
| TD | Tres difficile | Very difficult, sustained alpine climbing for experienced alpinists. | Complexity, objective hazard and sustained technical climbing dominate. |
| ED | Extremement difficile | Extremely difficult and highly committing alpine climbing. | Elite technical ability and high-level mountain judgment are assumed. |
Plus and minus modifiers matter.
Guidebooks commonly refine a broad Alpine grade with modifiers such as PD+, AD- or AD+. The exact description should come from the route source being used rather than from a generic conversion table.
Four Real Routes Show Why One Grade Is Never Enough
These routes already have full Global Summit Guide coverage, so you can move directly from the grading system into the actual mountain.
Longs Peak – Keyhole Route
The technical movement is scrambling rather than roped fifth-class rock, but the route adds altitude, a long day, route-finding, lightning exposure, loose rock and major fall consequence above the Keyhole.
Apply the grade to Longs Peak →Grand Teton – Owen-Spalding
5.4 describes the technical rock crux. It does not describe the long approach, altitude, exposed movement, route-finding, weather or technical descent.
Apply the grade to Grand Teton →Matterhorn – Hornli Ridge
The Alpine AD describes the entire ridge objective. The UIAA rock grade describes the hardest rock movement. Neither number alone captures the speed, altitude and serious same-route descent.
Apply the grades to Matterhorn →Eiger – Mittellegi Traverse
The Eiger illustrates why route name matters. The classic Mittellegi-to-South-Ridge traverse carries greater commitment than the Matterhorn normal route even when individual rock moves appear moderate in isolation.
Apply the grade to the Eiger →Route name belongs beside every grade.
“Matterhorn difficulty” or “Eiger difficulty” is incomplete without the route. One mountain can contain a standard route, a technical ridge and an elite face climb that live in completely different difficulty categories.
Mountain Difficulty Calculator
This calculator does not convert official climbing grades. Instead, it asks the second question: after you know the technical grade, how difficult is the complete mountain problem?
Estimated route difficulty
Dominant demand
Progression gap
The Global Summit Guide Level 1-6 Framework
This is a site-specific planning framework. It does not replace YDS, UIAA, French, Alpine or guidebook grades.
Intro Mountain
Trail hiking and straightforward mountain movement with easy retreat.
Long Nontechnical
Large hiking or scrambling objectives where fitness, altitude or exposure create the primary burden.
Intro Glacier
Crampons, ice axe, snow, glacier travel and rope-team systems enter the normal movement toolkit.
Technical Alpine
Sustained rock, snow, ice or mixed terrain where efficient transitions and descent competence are essential.
Expedition
Multi-day or multi-week objectives where altitude, cold, logistics and accumulated fatigue become defining problems.
Elite / Extreme
High-consequence technical objectives, 8,000-metre expeditions and elite alpine routes with little margin for error.
A Level 4 route is not automatically technically harder than every Level 5 route.
The GSG level describes the total planning burden. Matterhorn can demand harder rock movement than Aconcagua, while Aconcagua carries a much larger altitude and expedition burden. That is exactly why both systems are useful.
How to Use a Grade Before Choosing Your Next Mountain
The useful question is not merely “Can I climb this grade?” It is whether the complete route is one reasonable step beyond what you already do comfortably.
Identify Every Grade
Find the technical grade, overall Alpine grade, commitment grade and route-specific snow or ice information.
Read the Route Description
Understand length, approach, descent, exposure, objective hazards and normal turnaround points.
Compare to Experience
Use the hardest route you have completed competently, not the hardest route you survived.
Close One Gap
Build the missing skill – scrambling, rope systems, glacier travel, altitude, endurance or expedition experience – before adding several gaps at once.
New to the system?
Start with the Beginner Mountain Climbing Guide and then use the progression plans to build one type of mountain competence at a time.
Mountain Difficulty Rating FAQ
The distinctions that prevent most grade-system confusion.
What is the Yosemite Decimal System?
YDS is widely used in North America. Class 1 is hiking, Classes 2 and 3 cover increasingly involved scrambling, Class 4 is exposed simple climbing where a rope is often used, and Class 5 is technical rock subdivided into grades such as 5.6 and 5.10a.
What do F, PD, AD, D, TD and ED mean?
They are French adjectival overall Alpine grades: F is facile, PD peu difficile, AD assez difficile, D difficile, TD tres difficile and ED extremely difficult. They describe the whole alpine objective rather than only one crux move.
Can YDS, UIAA and French grades be converted?
Fifth-class YDS, UIAA rock and French free-climbing grades can be compared approximately. UIAA publishes comparison tables, but the match is not exact and becomes especially imperfect between regional traditions. Overall Alpine grades such as AD and D are a different type of rating and should not be directly converted.
What is the difference between French 6a and Alpine AD?
French 6a is a technical free-rock-climbing grade. Alpine AD is an overall route grade. A route rated AD might contain rock much easier than French 6a but still earn AD because of length, exposure, snow, ice, altitude, route-finding or commitment.
Is Class 3 safe without a rope?
Not automatically. Class 3 describes movement difficulty, not a guarantee of low consequence. Some Class 3 routes contain terrain where a fall would be fatal. Experience, exposure tolerance, conditions and route choice still matter.
Why does one mountain sometimes have several grades?
Because the mountain contains different routes and because one route may be described by several systems at once. Matterhorn’s Hornli Ridge, for example, can have an overall Alpine grade and a separate UIAA rock grade.
Is the GSG Level 1-6 scale an official climbing grade?
No. It is Global Summit Guide’s planning framework. It adds fitness, altitude, weather, objective hazard, remoteness and retreat complexity to the technical information supplied by established grading systems.
How the Grade Tables Were Built
Cross-system comparisons use published federation material wherever possible rather than crowdsourced conversion charts.
Primary grading references
- UIAA – Rock Climbing Grades for UIAA history, definitions, Alpine global assessment and comparison context.
- UIAA published cross-system tables for approximate YDS, French and UIAA rock-grade relationships.
- National Park Service documentation for the definitions of YDS Classes 1 through 5.
- British Mountaineering Council alpine-route resources for real-route grading examples.
What this guide does not claim
- No conversion table is mathematically exact.
- Regional grading traditions differ.
- Conditions can change effective difficulty.
- A mountain does not have one universal grade independent of route.
- The GSG Level 1-6 framework is not an industry standard.
- Grade alone cannot determine whether an individual climber is ready.
Move From Difficulty Rating to the Right Next Mountain
Use the grading system to understand the terrain, then use progression planning and real mountain guides to understand the complete objective.
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Global Summit Guide is an independent mountaineering resource founded in 2026. The team combines first-hand trekking and climbing experience with in-depth research and professional health and nutrition review to help climbers choose objectives, prepare properly, and stay safe.
Health, altitude, and nutrition content is reviewed by Taylor Ludlow (Registered Nurse) and Brigg Hoopes (Nutritionist).
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