Understanding

Climbing

Scales:

How

to

Read

the

Numbers

on

the

Wall

The Purpose of a Good Climbing Scale

When rating climbing routes, many factors come into play: wall angle, hold size, foothold variety – these can still be measured relatively objectively. However, it gets trickier when rock quality, aspect, or visibility enter the picture. Some walls may cast nasty shadows in the afternoon, and holds become nearly invisible. Conversely, if you’re short in built, you sometimes may have no other choice but to basically jump from one hold to another – or accept your fate, abandon your mission and climb down with as much dignity as possible.

Then there are things like temperature and humidity to consider: what seems doable in cool, dry weather becomes a slip-fest in summer. Also, climbing routes are never static. Holds wear down, break off – and thus, a solid 5.11a can easily turn into a 5.12a overnight. Keep in mind that grading involves subjective factors that make up a general consensus. What feels like a 5.9 to you might be a 5.10a to someone else.

In short: A rating system can only ever be an attempt to capture all these aspects in a single value. And that's exactly where the challenge lies.

The Most Common Climbing Grading Scales

Rating systems differ by country, discipline, and tradition – but they’re all indicators of the difficulty of a route. Some also factor in the amount of commitment and safety as part of the overall assessment. Sport climbing routes are often rated using the French system, while bouldering typically uses the Fontainebleau system. The British grading system even takes it one step further, additionally indicating the level of protection, exposure, as well as the fall risk. To get you ready for your next climbing trip, here’s an overview of the most common rating systems:

French Climbing Scale

As mentioned before, the French scale has established itself as the standard in sport climbing, especially in Europe, but also internationally. Starting at 1 (very easy), the scale progresses through 4, 5, 6, etc. all the way up to (currently) 9c. From grade 5 onward, letters (a, b, c) and subdivisions like "+" are used – for example, 7a, 7a+, 7b, etc. A route graded 7a+ is therefore harder than 7a, but easier than 7b. This is followed by 7b+, then 7c, 7c+, before continuing with 8a.

However, a French 7a+ isn't identical to the same rating in other systems – especially not in climbing halls outside Europe.

UIAA: The International Climbing Difficulty Scale

The UIAA scale (Union International des Associations d'Alpinisme) is similar to the French scale, but uses Roman numerals. You'll most likely encounter it in Germany, Austria, and Switzerland, as well as on traditional alpine climbing routes.

It currently ranges from I (very easy) to XII (extremely difficult) – with higher grades using additions like "-", "plain", and "+". If you already understand how the French scale works, this one will be easy for you to work out. The difficulty grades from easy to hard would be, for example, V-, V, V+, VI-, etc.

Saxon Difficulty Scale

In the Elbe Sandstone Mountains and adjacent regions, the Saxon scale applies. It combines technical difficulty and risk in one rating, using Roman numerals like the UIAA scale. From VII onward, it's further subdivided with letters, e.g. VIIa, VIIb, VIIc, and so on.

Belaying conditions are particularly challenging there – in short, it’s traditional climbing ("Trad") with a lot of personal responsibility.

USA’s Yosemite Decimal System

In the United States, the Yosemite Decimal System (YDS) is used – also called the Sierra scale. It starts at 5.0 and currently goes up to 5.15d. From 5.10 onward, letters from "a" to "d" are added – e.g., 5.10a, 5.10b, etc. –, following the classification system of the French and Saxon scales.

The YDS is frequently used in sport and trad climbing, but focuses purely on rating physical difficulty.

British Grading System

In Great Britain, things get a bit more complex. Here, the E-scale ("Effort") is used to evaluate not only technical difficulty, but also psychological stress and belaying conditions. It’s made up of the following components:

• Technical Grade (e.g., 4c, 5b, 6a) denotes the technically single most challenging part of the route.

• Adjectival Grade (e.g., S "Severe", HS "Hard Severe", E1 to E11) evaluates the entire route – including available protection, exposure, and fall risk.

This means that a route may be considered easy on a technical scale, but still receive a high E-rating if protection is poor or even poses potential danger for climbers.

Australia: Simply Count Up

While the E-scale represents the highest level of complexity, Australia keeps it much simpler. It starts around 11 (easy) and currently goes up to 36, which roughly corresponds to French 9a or UIAA XI. There are no letters or plus-minus divisions – you simply count up. However, routes can feel very different to navigate depending on the area and terrain.

Brazilian Scale

If you're planning a climbing trip to South America, you should definitely take the time to familiarize yourself with the Brazilian rating system. Like the UIAA or Saxon scale, it relies on Roman numerals from I–XI. Easy routes up to rating VI can be supplemented with "sup" (for "superior"), e.g., VIsup. From grade VII onward, the letters a, b, and c are added, following the French model to further differentiate between difficulty levels.

Aid Climbing – What Do A0, A1 & Co. Mean?

In aid climbing, you actively use protection for upward progress. Here are the key grades:

• A0: Protection point used as step or hold ("aiding")

• A1: Movement with foot loops

• A2-A5: Increasing in difficulty, anchors progressively deteriorating, high risk

Rating Systems in Bouldering

The previous rating scales all focused on rope climbing. Bouldering, however, looks quite different. Here, the focus is on measuring explosive power and perfect movement sequences – but not endurance, tactics, or protection. Compared to sport climbing, you’d be looking at  something like a 100-meter sprint vs. a marathon.

When bouldering, you'll sooner or later encounter the Fontainebleau scale (short: Fb) – it's the gold standard, especially in Europe. It comes, as the name suggests, from the legendary bouldering area Fontainebleau in France, and is pretty close to the French rating for climbing routes.

The scale begins at 2 ("easy"), increasing in a-, b-, and c-incriments up to level 5. From 6a it gets serious, and ratings are either straight or marked with a "+" – meaning the boulder is a touch more difficult. If you want to know where the absolute top lies: the hardest confirmed boulder so far is 9a – a serious benchmark!

Then there's the Fb traverse rating. The principle remains the same, but since traverses are usually more endurance-based and less explosive, they're rated somewhat easier. An 8a+ traverse therefore corresponds roughly to an 8a boulder.

If you ever go bouldering in the US, you'll eventually come across the V-scale. It's the leading rating system there and works a bit differently than the Fontainebleau scale. The "V" stands for "Vermin", named after boulderer John "Vermin" Sherman, who created the system.

It starts at V0, which roughly corresponds to 5c on the FB scale. After that, difficulty increases linearly: V1, V2, V3... and so on, up to currently V17 (corresponding to a 9a boulder) – the hardest confirmed boulder crux in the world. Unlike the Fb scale, there are no a-, b-, or c-subdivisions here, making things a little bit more linear.

Can Difficulty Grades Be Easily Converted?

The short answer: No – at least not exactly. While there are numerous comparison tables and converters, there's often still a lot of wiggle room. A French 6c isn't always as hard as UIAA 8, and even if a boulderer masters 7a, that doesn't automatically mean they can also do a 9+ sport climbing route – because both disciplines require completely different skills. While sport climbing primarily requires technique, endurance, and strategic route reading, bouldering is often about precise movements, body tension, and dynamic elements – but also complex technique, balance, and problem-solving skills. In trad climbing, mental factors like self-belaying, risk assessment, and route assessment are additionally important.

We recommend using tables purely as guidelines – especially within your own performance abilities – and to always expect the unexpected.

Climbing Scale Comparison Table

Source: Alpenverein 

Gym vs. Rock Climbing

Even though indoor routes are often rated using the same scales as outdoor routes, there are important differences:

• Indoors: easier to assess, consistent spacing between holds, consistent temperatures

• Rock: Uneven, unpredictable, natural belaying points – but also include the one or other surprise, which correspondingly makes them more psychologically demanding

Climbing halls are often considered "customer-friendly" – which can lead to a serious reality check when you’re outdoors. Especially when engaging in challenging onsight-climbs, it pays off big time if you’re already acquainted with the feel and physics of rocky surfaces.

Conclusion: Understanding Rock Climbing Scales – and Using Them Wisely

Climbing is more than just numbers, letters, and scales. Every route tells its own story – and difficulty is never just a question of grade. With a basic understanding of different rating systems and an open eye for subjective factors, you’ll be able to much better assess your routes – and specifically train for them.

Whether indoors or out in the wild, the main thing is to keep going – and have fun on the wall!