Grade comparison tables, side by side.

Why the tables differ

Every body consulted in our research says conversions between grade scales are approximate. The UIAA's grades page says so directly, and lists route length, style, continuity, rock type, protection, exposure and conditions as things that change how hard a climb feels. The Italian Alpine Club (CAI) paper by G. Mandelli and A. Angriman, hosted by the UIAA and undated, explains that grades are subjective and shaped by local habits. Mountain Project's own chart says no conversion chart is perfect. British grades mix risk with difficulty, so tables differ most when they include them.

Because of that, this page does not offer one "correct" conversion. It gives each publisher's pairings as that publisher states them. A blank cell means the publisher gave no pairing for that grade in the material our research read. The scales themselves are explained on the grading systems page.

The tables as published

Mountain Project international chart

Mountain Project (operated by onX Maps; page undated, read 21 October 2026) pairs five rock scales in one chart. Only the four rows below were confirmed against the live chart on 21 October 2026. Other rows our research read from the page's flattened text could not be confirmed, so they are left out.

CAI "plaisir" table (UIAA and French)

The CAI paper reproduces a table from the Buscaini archive pairing UIAA and French grades. Where it gives two French grades, both are shown.

BMC typical British pairings

The BMC (British Mountaineering Council) pairs the two parts of the British grade with each other, not with other scales. It calls these typical pairings and guidelines: S 4a, HS 4b, VS 4c, HVS 5a, E1 5b, E2 5c, with 6b typical by E6.

Single pairings from other publishers

• Wikipedia pairs French 8a with YDS 5.13b, UIAA X- and Ewbank 29, and in its text equates French 7a+ with UIAA VIII.
• Sendy (a climbing app's chart, secondary) puts UIAA V at YDS 5.8, YDS 5.8 at French 5a, and YDS 5.10a at French 5c.
• Hong Kong Climbing (secondary) puts YDS 5.4 at UIAA IV.
• The CAI paper says YDS 5.0 corresponds to UIAA III, and records that Francois Labande, in the late 1980s, placed French 6a where UIAA VI+ had been.
• Mammut (maker, July 2025) pairs V0 with roughly Font 5c, and warns that a French 6c is not always as hard as a UIAA VIII. The rest of its chart is published only as an image, so our research could not read it.

Mountain Project bouldering chart

As with the rock chart, only the rows confirmed against the live chart on 21 October 2026 are shown.

Wikipedia gives one fixed point at the top: Burden of Dreams is graded V17 and Font 9A. That is the grade of one problem on both scales, not a conversion table.

Side by side: UIAA to French

Each column is one publisher's pairing, unchanged. The Mountain Project column uses only its confirmed rows.

Side by side: YDS to French and UIAA

The CAI paper also records a historical comparison: in the early 1970s, the American 5.10 was compared to the European grade VII. On Mountain Project's current chart, the confirmed rows put 5.9 at UIAA VI and 5.11a at VII+.

Every disagreement, flagged in our research or visible in the tables above

UIAA VIII and French 7a

The CAI plaisir table puts UIAA VIII at French 7a. Wikipedia's text equates French 7a+ with UIAA VIII. Our research also read Mountain Project's chart as putting UIAA VIII at 7a, but that row could not be confirmed against the live chart.

UIAA V and YDS

Mountain Project puts UIAA V at 5.6. Sendy's chart puts UIAA V at 5.8. Hong Kong Climbing's table puts 5.4 at UIAA IV.

YDS 5.10a and French

Wikipedia puts 5.10a at French 6a. Sendy puts it at French 5c, while Mountain Project's confirmed rows put French 5c at 5.9. Our research also read Mountain Project's chart as putting 5.10a at French 6a, but that row could not be confirmed against the live chart.

British grades

Our research read Mountain Project's chart as putting YDS 5.8 at HVS 4c, while the BMC's typical pairings put HVS with 5a and VS with 4c; that Mountain Project row could not be confirmed against the live chart. In its confirmed rows, Mountain Project lists S 4b, where the BMC's typical pairing is S 4a.

V0 and Font

Mountain Project pairs V0 with Font 4. Mammut (2025, maker) pairs V0 with roughly Font 5c.

5.10 over time

In the early 1970s 5.10 was compared to UIAA VII, according to the CAI paper; Mountain Project's confirmed rows put 5.9 at VI and 5.11a at VII+, and give no confirmed pairing for 5.10 itself.

Tables we could not read

The UIAA publishes its worldwide comparison table only as an image on its grades page, and Mammut's chart is also an image. Neither could be read as text, so neither appears here. The CAI paper notes that the UIAA has produced comparison tables over the years, though few guidebook authors refer to them. The site also has a grade comparison tool for looking up one grade at a time.