The French climbing scale: 6a, 7b+ and what the letters mean

The scale hanging in most gyms

“6b+”, “7a”, “8c” — when a route carries an Arabic numeral with a small letter after it, you are reading the French scale. It is the youngest of the three roped climbing scales in supra-regional use, the predominant one in Europe and one of the two most used worldwide.

What is remarkable is how quickly that happened. The UIAA scale took more than seventy years from its beginnings to official recognition. The French scale emerged in the 1980s, almost incidentally, in guidebooks — and had conquered the gyms within a generation.

Number, letter, plus — and nothing else

The structure is explained in one sentence: an Arabic numeral for the rough band, a small letter a, b or c for the step within it, and optionally a “+” for the half step above. That gives a fixed order: 6a, 6a+, 6b, 6b+, 6c, 6c+ — and then the next number begins at 7a.

Six steps per numeral is twice as many as the UIAA scale offers with its three gradations per grade. That is precisely why the French scale prevailed in sport climbing: where routes set close together have to be graded, fine steps are needed. For an alpine multi-pitch route, whose difficulty varies across its length anyway, that fineness would be false precision.

At the bottom end the scale reaches down to the numeral 1 according to the English-language account. In comparison tables and everyday gym use, however, it usually only appears where the letters begin — below that lies terrain hardly anyone grades any more.

There is no minus — and that has consequences

A detail that stands out constantly in everyday use and is rarely explained: the French scale knows only upgrading with “+”, but no downgrading with “−”. There is 7a+, there is no 7a−. The UIAA scale uses both.

That sounds like a formality, but it changes how grades are given. Anyone who considers a route slightly too easy for its grade has no notation for it — they must place it a full step lower or stay at the full grade. Borderline cases therefore slide systematically in one of the two directions, and that is where a good part of the endless discussions about whether a route is graded “soft” or “hard” comes from.

It emerged because the UIAA scale was no longer enough

In the early 1980s the new grading appeared in French guidebooks. At first it was not a scale of its own at all but a stopgap: the Roman numerals of the UIAA scale were kept and a letter appended — VIa, VIb. Other guides wrote in Arabic straight away: 6a, 6b.

The cause was the same as with Benesch and Welzenbach decades earlier. Sport climbing produced routes for which the existing steps were too coarse, and a scale that can only refine with “+” and “−” eventually hits its limit. The difference from 1923: this time the scale was not extended but subdivided more finely.

François Labande and the Arabic numerals

Order was brought to this coexistence towards the end of the 1980s by François Labande. He was a French mountaineer and guidebook author, born in 1941 in Toulon, an engineer and mathematics teacher by background, who took over the editorship of the Guide Vallot from Lucien Devies in 1987 — the standard guides to Mont Blanc and the Haut-Dauphiné. Between 1980 and 2006 he published numerous climbing, ski and walking guides.

Labande presented the French scale in the form used today: Roman numerals permanently replaced by Arabic ones, and the value 6a placed where VI+ had been. That single anchor point is the reason the two scales can be translated into each other at all.

He was evidently not entirely convinced himself. A few years later he used Roman numerals again in his Dauphiné guide — V+, VIa, VIb — and expressly left open how VIa and 6a relate to each other. The Arabic version prevailed nonetheless; it is still aligned with the UIAA scale today.

Labande stayed connected to the mountains beyond his guidebooks: he founded the French branch of Mountain Wilderness and chaired it from 1995 to 2002; in 1999 he was appointed a Knight of the Legion of Honour. He died in March 2025 in La Salle-les-Alpes.

Why the conversion still does not come out cleanly

A single anchor point holds two scales together only where it was set. Above it they diverge, because they are graded with different fineness: one offers six steps per numeral, the other three. What began lower down as a clean correspondence becomes, higher up, a matching in which there are steps of one scale for which the other gives no grade of its own.

That is why there is no comparison table here. Which French grade corresponds to which UIAA grade and to which value in the Yosemite Decimal System is set out in full in the climbing grade converter — where the gaps are shown as gaps rather than rounded to a neighbouring value.

Three mix-ups that keep happening

Upper and lower case. 6a and 6A look almost the same and belong to different scales. Lower case is the French sport climbing scale, upper case the Fontainebleau scale for bouldering. The difference is not a subtlety: a Font grade sits considerably higher than the same string of characters would lead you to expect in roped climbing. To make this unambiguous, the small prefix “f” is also common — f6a+ — while boulders are marked with “F” or “fb”.

The French alpine scale. France has a second, entirely different grading system that is also called “French”. It consists of letter abbreviations and assesses not the climbing technique but the undertaking as a whole: length, technical difficulty, exposure and commitment.

This scale too was climbed past: refinement happens with “+” and “−”, and the top level is now numbered through as ED1, ED2, ED3 and beyond. A route can carry both an alpine code and a numerical grade — one says what you are letting yourself in for, the other how hard the hardest pitch is.

The British E grades. In the United Kingdom routes carry designations such as “E4 6a”. The second part is a British technical grade and not the French one — another reason for the small “f” when unambiguity is called for.

It grades the movement only, not the risk

The French scale measures technical climbing difficulty and nothing else. How far apart the bolts are, how hard a fall turns out to be or how serious the situation becomes if something goes wrong does not enter the grade. That is not negligence but suits the climbing the scale was made for: pre-bolted sport climbing, in which protection is taken as given.

This is exactly where it differs from the Yosemite Decimal System and even more clearly from the British E grades, which grade the risk as well. Anyone reading a French number learns how hard the movements are — and nothing about what happens if they fail.

Open-ended: 9c

Unlike the UIAA scale, the French one never had to be opened — it was open from the start. The highest grade awarded so far is 9c. It sits on a single route: Silence, 45 metres long, in the Hanshelleren cave near Flatanger in Norway. Adam Ondra was the first to free-climb it on 3 September 2017, after around 40 climbing days across seven visits.

As of July 2026 it has remained unrepeated. Two climbers have so far managed the crux — Stefano Ghisolfi in May 2024 and Will Bosi in May 2026 — but nobody other than Ondra has done the complete route. A grade confirmed so far by exactly one person on exactly one route is therefore less a step than a proposal: it stands until a second ascent confirms or corrects it.

Where you meet the scale today

In Europe practically everywhere in sport climbing, in many gyms exclusively, and worldwide as one of the two most common scales alongside the Yosemite Decimal System. Even in German-speaking countries, the home of the UIAA scale, sport climbing routes are increasingly labelled in French as well.

In practice that means you will see both notations — the same gym can label the wall in French and keep UIAA grades in its route book. All that matters is that you know which scale you are reading and that you do not mix them up when recording.

Frequently asked questions

What do the letters a, b and c mean?

They subdivide a number into three steps: 6a is easier than 6b, 6b easier than 6c. Together with the “+” this gives six steps per number — 6a, 6a+, 6b, 6b+, 6c, 6c+ — before the next number begins at 7a. The letters are lower case. Capitals such as 6A belong to the Fontainebleau scale for bouldering and denote something different.

Why is there a 6a+ but no 6a−?

Because the French scale only knows upgrading with “+” and no downgrading with “−”. That is the most striking difference from the UIAA scale, which uses both. In practice it means that anyone who considers a route slightly too easy for its grade cannot express that in the grade — they would have to place it a full step lower.

Is a French 6a the same as a Font 6A?

No, and the confusion has consequences. The French sport climbing scale uses lower case (6a), the Fontainebleau bouldering scale capitals (6A). They measure different things on different ladders; a Font grade sits considerably higher than the same string of characters suggests in roped climbing. That is why the climbing grade converter on this site keeps bouldering and roped climbing in two separate tables, between which no conversion is possible at all.

What is the difference between 6a and AD?

They are two different French systems. Number-letter grades such as 6a assess the technical climbing difficulty of a route or pitch. The abbreviations F, PD, AD, D, TD and ED assess an alpine undertaking as a whole — length, exposure, seriousness and commitment. A route can therefore carry both an AD and a 5c without any contradiction.

How far up does the scale go?

It is open-ended. The highest grade awarded so far is 9c, proposed by Adam Ondra for the route Silence in the Hanshelleren cave near Flatanger in Norway, which he was the first to free-climb on 3 September 2017. It had not been repeated as of July 2026; individual climbers have so far only repeated the crux.

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