Climbing Grade Converter
YDS to French and UIAA climbing grades.
What it does
Climbing grades translate approximately, never exactly. YDS 5.9 reads French 5b with UIAA VI-, 5.10a reads 5c with VI, and 5.12a reads 7a+ with VIII+, yet neighboring tables split rows by half steps. History, not physics, sets each scale.
The tool above converts eleven YDS grades to French and UIAA with variance notes attached. AAC chart rows anchor each conversion while UIAA worldwide ranges flag splits like VI+ spanning 5c+/6a. Defaults show 5.9; 5.10a notes its VI+ upper end.
Both authorities warn against precision. UIAA parameterizes French grades against its Roman scale with open-ended history, and the American Alpine Club chart carries the same rows with guidebook drift acknowledged. French-first tables shift neighbors by half steps either way.
Local grades rule real climbing. Gym tags, crag guides, and setter styles all drift from charts, so convert for travel planning then confirm on rock. Log sends in home grades to track progress honestly.
How to use
- Pick the YDS grade.
- Read French first, then UIAA.
- Read the variance note.
- Confirm with local guidebooks.
- Expect half-step drift.
- Log sends in home grades.
Formula
- YDS
- YDS grade selector, 5.8 to 5.12d.
AAC comparison chart with UIAA worldwide table; both state approximations with half-step guidebook drift.
Worked example
Example: YDS 5.9
Defaults: YDS 5.9.
- Input: YDS 5.9.
- French: 5b per AAC chart.
- UIAA: VI- per AAC and worldwide table.
- Note: systems overlap; guidebooks vary half steps.
- Tool shows French 5b, UIAA VI-.
Reference table
| YDS | French | UIAA |
|---|---|---|
| 5.8 | 5a | V+ |
| 5.9 | 5b | VI- |
| 5.10a | 5c | VI |
| 5.10d | 6b | VII |
| 5.11a | 6b+ | VII+ |
| 5.12a | 7a+ | VIII+ |
Limits
- Approximate only. No exact mapping exists.
- Eleven grades only; extremes excluded.
- Aid and ice grades separate.
- Gym tags drift from charts.
Common mistakes
- Treating conversions as exact.
- Ignoring half-step guidebook drift.
- Mixing French-first with AAC rows.
- Training zones off wrong grades.
- Skipping local confirmation.
Try it yourself
Quick checks. Answers sit tucked under each question.
YDS 5.10a?
AAC: French 5c, UIAA VI. UIAA table notes VI+ upper end.
YDS 5.12a?
AAC: French 7a+, UIAA VIII+. Matches UIAA VIII+ = 5.12a/5.12b.
Questions
How do grades convert?
AAC chart rows: 5.9 to 5b/VI-, 5.10a to 5c/VI, 5.12a to 7a+/VIII+.
Are conversions exact?
No. Systems grew separately; rows overlap and guidebooks shift half steps.
Why do tables disagree?
UIAA worldwide tables show ranges (e.g. VI+ spans 5c+/6a). The note line flags splits.
Does AAC include UIAA?
Yes. AAC rows carry UIAA equivalents from V+ through IX.
Where does French 6a land?
Yes. French 6a sits at VI+ while neighboring rows split across systems.
Should I trust gym tags?
Yes. Confirm locally; gym and crag grades drift from charts.