Grades are opinions
Conversion tables are approximations: Mountain Project itself says no conversion chart is perfect. This tool shows what each table says; it does not tell you whether a route is within your ability.
How it works
Each row in the tool is one pairing exactly as one publisher gives it. The Mountain Project rows are the ones we checked against its live chart on 21 October 2026; its other rows are left out because we could not confirm them. The CAI table, hosted by the UIAA, pairs UIAA and French grades only. Wikipedia, the Sendy app chart and Hong Kong Climbing are secondary sources, and Mammut's bouldering pairing is a maker's rough guide.
The tool never merges, averages or fills in the tables. Where two publishers pair the same grade with grades that do not overlap, both rows appear and the tool says the tables disagree; one publisher giving two rows, or ranges that share a grade, is not counted as a disagreement. British grades mix risk with difficulty, which is one reason tables differ most there.
Sources
- Mountain Project, International Climbing Grade Comparison Chart (onX, undated; rows checked 21 October 2026)
- CAI paper on the scales of difficulty in climbing, hosted by the UIAA (Buscaini table)
- Wikipedia, Grade (climbing) (secondary)
- Sendy, climbing grade conversion chart (app publisher, secondary)
- Hong Kong Climbing, grade tables (secondary)
- Mammut, understanding climbing scales (2025, maker)