Climbing Grade Converter

How to use the climbing grade converter

1. Select your source climbing system from the dropdown (for example, V-scale, YDS, French, British trad, UIAA, Ewbank, or Font).
2. Type the grade you want to convert as you would write it in a guidebook (for example, V4, 5.11b, 6b+, E2 5c, VIII-, 22, or 7A+).
3. Select Convert grade to see equivalents in every other system, together with the neighbouring difficulty bands.
4. Select Reset to clear the field and start again.

The input is forgiving. Case does not matter, extra spaces are collapsed, and several common shorthands are accepted: 10c is read as YDS 5.10c, a bare 4 is read as V4 when the source system is the V-scale, and an adjectival-only British entry such as HVS or E3 is matched to the lowest band that carries that adjectival grade. If a grade cannot be matched, the converter says so and lists valid examples for the system you selected instead of printing a blank or a nonsense value.

Conceptual relationship between grade systems

Although each grading system has its own history and style, they all try to express the same underlying idea: how physically, technically, and mentally difficult a climb is. A simple way to think about this is to break the challenge into three components:

Formula: R = M + E + P

where:

• R is the overall perceived route difficulty,
• M is the hardest individual moves or boulder problem,
• E is the endurance or pump factor over the length of the climb, and
• P is the psychological and protection factor (exposure, runouts, fall consequences).

Different systems weight these factors differently:

• V-scale and Font (bouldering) are dominated by M, the hardest moves, with almost no weight on endurance or protection.
• Yosemite Decimal System (YDS) blends M and E, with only a rough, indirect nod to protection through optional R and X suffixes.
• French sport grades focus on overall sustained difficulty (M + E) for bolted routes.
• British traditional grades separate M and P explicitly by publishing an adjectival grade (overall seriousness) alongside a technical grade (hardest move).
• UIAA and Ewbank grades sit conceptually between YDS and French systems, with their own regional traditions.

The conversion formula: a band lookup, not arithmetic

There is no arithmetic formula for grade conversion, because each system is an ordered list of named bands rather than a number line. The converter stores a single master table T in which every row is one difficulty band and every column is one grading system. Conversion is a two-step lookup. First, find the band index whose entry in the source system matches your grade:

Formula: b = {i: T_i,s = g}

Then read the same row in the target column:

Formula: C(g, s, t) = T_b,t

Here g is the grade you typed, s is the source system column, t is the target system column, and b is the band index. The mapping is deliberately many-to-one in both directions. A single V-scale entry such as V4 occupies two rows of the table (5.11d and 5.12a), so converting V4 to YDS returns the first of those rows while converting either YDS grade back returns V4. Round-tripping a grade through two systems therefore does not always return the grade you started with, and that is a property of the scales, not a bug in the lookup.

The number of distinct labels each system uses over the same span of difficulty is itself informative. Across the 27 bands in this table the YDS contributes 27 distinct labels, French 27, UIAA 27, the Ewbank scale 26, the V-scale only 18 and Font only 18. That count difference is exactly why boulder grades feel coarse when you translate them into route grades.

Worked example: converting French 6b+ for a United States trip

Suppose you climb comfortably around French 6b+ at your local sport crag and you are planning a trip to the United States. You want to know which YDS and V-scale grades will feel similar.

1. Choose French sport grades as the source system.
2. Enter 6b+ as the source grade.
3. Select Convert grade.

The converter finds 6b+ in band 8 of 27 and reads across that row:

• YDS: 5.10d,
• UIAA: VII,
• British trad: E2 5c, meaning a serious E2 lead whose hardest single move is 5c,
• Ewbank: 20,
• V-scale: V2, with Font 5+ as the European bouldering equivalent.

If you normally onsight many 6b+ routes, you might expect to feel similarly comfortable on well-protected 5.10d and easy 5.11a sport routes in the US. The single hardest move on such a route can still feel like a V3 or V4 boulder problem, which is why crux move grades often sit above a route's overall equivalent. Notice too that band 7 and band 8 both carry Ewbank 20: the Ewbank scale simply has no step between 5.10c and 5.10d, so an Australian guidebook cannot express that distinction at all.

Cross-system grade comparison table

The exact mapping between systems is not universal, but the table below shows commonly accepted approximate equivalences spanning easy to elite difficulty. The converter uses a fuller internal table of 27 bands; this excerpt shows every third band so the shape of the alignment is visible at a glance.

Use these ranges as a ballpark reference, not as strict rules. Individual routes can feel easier or harder than their nominal grade, especially when they favour or punish your personal strengths.

Reading British trad grades: two numbers, not one

Britain is the only major system in this table that publishes two grades for every route, and the pair is the whole point. The adjectival grade runs Moderate, Difficult, Very Difficult, Severe, Hard Severe, Very Severe, Hard Very Severe, then E1, E2, E3 and upwards. It answers the question "how much of an undertaking is this lead?" and folds in sustainedness, strenuousness, the quality of the protection, and the consequence of a fall. The technical grade (4a, 4b, 4c, 5a, 5b, 5c, 6a, 6b, 6c, 7a) answers a narrower question: how hard is the single hardest move?

Reading the pair together is what tells you what kind of day you are in for. E1 5b is the "normal" pairing: a route whose difficulty is spread out and whose gear is reasonable. E1 5a with an easier technical grade almost always means the route is bold, run out, or on suspect rock, because something other than the moves pushed the adjectival grade up. E1 5c with a harder technical grade usually means a short, sharp, well-protected crux above good gear. Any converter that collapses this pair into a single number, as this one must in order to line British trad up against the others, has thrown away the information a British climber actually uses to choose a route.

Why the scales diverge at the top end

Below about YDS 5.12 the systems track each other closely, because tens of thousands of climbs have been graded in every system and consensus has had decades to settle. Above that the alignment becomes an extrapolation, for three concrete reasons.

• The step sizes differ. The YDS splits each number into four letters (a, b, c, d) while French splits each number into three steps (for example 8a, 8a+, 8b). Two scales cannot stay in step forever when one takes four strides per number and the other takes three.
• The scales are open-ended and were extended independently. Each new hardest-in-the-world climb added a step to whichever scale its first ascensionist used, and the other communities back-filled afterwards from video and second ascents rather than from their own consensus.
• The sample sizes collapse. There are only a handful of routes in the world at 5.15c, and British E10 and E11 rest on a few dozen climbs by a few climbers. Grades built on such small samples cannot be averaged in the way that grades at 5.10 can.

A practical consequence: two reputable charts can differ by a full step at the top of the table while agreeing perfectly in the middle. The bouldering scales diverge from the route scales in a different way again. The V-scale and Font contribute only 18 distinct labels across the same difficulty span in which the YDS uses 27, so each boulder grade absorbs roughly one and a half route grades, and the mismatch is systematic rather than random.

Interpreting your climbing-grade results

When you convert a grade, the output is an approximation of where that climb would sit in other systems if climbers in that region had graded it. Expect small disagreements between guidebooks, online databases, and local climbers. That is normal and reflects the subjective nature of grading.

A few practical tips:

• Treat the converted grade as a starting point when choosing climbs, then adjust up or down based on how stiff or soft you find the area.
• For bouldering versus route comparisons, remember that a V-grade or Font grade mainly describes the hardest move, while a route grade also includes how long and pumpy the climb is.
• On traditional climbs, the adjectival component in the British system or the reputation of a route ("serious", "bold") matters more than its nominal difficulty when you decide whether it is appropriate.
• Read the neighbouring bands the converter prints alongside your result. If your project sits one band either side of a boundary, that spread is a better description of what you will meet than the single row.

Limitations and assumptions of grade conversion

Climbing grades are notoriously subjective. Two climbers of different heights, styles, and strengths can have very different experiences on the same line. Any converter must therefore make simplifying assumptions. This calculator assumes the following:

• Average conditions. Grades are calibrated for typical dry rock and standard conditions, not unusual heat, humidity, or polish.
• Modern consensus. Old sandbagged routes or newly upgraded climbs may sit outside the ranges used here.
• Rounded difficulty. The tool returns the nearest commonly used grade rather than a fractional or in-between value.
• Route style neutrality. It does not distinguish between slabs, overhangs, crack climbs, or endurance pitches, even though these style differences strongly affect your personal perception of difficulty.
• Trad versus sport simplification. For British, YDS, and Ewbank grades, the psychological and protection aspects are not modelled separately in the lookup; the British column collapses a two-part grade into one cell.
• No bouldering sub-grades. The V-scale and Font columns are blank for the three easiest bands, because those difficulties fall below where the bouldering scales are normally used.

Because of these limitations, you should not use the output as a safety guarantee. Always back off or down-climb if something feels harder or more serious than the converted grade led you to expect.

About these grade conversions

The equivalences used in this calculator follow the widely circulated comparison charts published by guidebook publishers, climbing magazines, and national federations, cross-checked against the summary tables maintained on Wikipedia and the bouldering conversion published by the American Alpine Club. There is no single official conversion endorsed by all organisations, so every chart, including this one, represents an informed best effort.

When reputable sources disagreed on specific crossover points, the mapping follows the middle of the common range rather than the most aggressive or the softest interpretation. The British column was corrected at the easy end, where several online charts print Mild Very Severe against YDS 5.6 and 5.7; the standard alignment used here places 5.6 at Severe 4b, 5.7 at Hard Severe 4b, and 5.8 at Very Severe 4c. The goal is a tool that feels reasonable to most climbers most of the time, not to settle grading debates.

When conversions are most and least reliable

Conversions tend to be most reliable when:

• You are comparing modern sport crags between regions where grades have been updated and consensus is strong.
• You have a decent sample of routes at a given grade and can mentally average your experience.
• The routes are of similar style (for example, vertical face climbing on well-bolted limestone in two different countries).

They tend to be least reliable when:

• You are looking at single famous sandbags or historically undergraded areas.
• The comparison spans very different styles, such as short, powerful boulders versus long pumpy pitches.
• You are near the limits of current difficulty, where consensus is still evolving and the sample of climbs is tiny.
• Protection quality or fall consequences dominate the experience, as on bold traditional lines.

Use the converter as one of several tools: combine it with local advice, guidebook descriptions, and your own judgement when choosing what to try.