What are bouldering grades?
Bouldering grades say how hard a boulder problem is. UK walls and crags use two systems, Font (such as 6A or 7B+) and the V-Scale (such as V3 or V8), and The Summit Social lets you log a boulder in either. Checked 29 October 2026.
Font
Font comes from Fontainebleau in France and can be traced back to at least 1960. A Font grade is a number and a letter, A, B or C, with a + for a little harder, so 6A, 6A+, 6B. The scale has no top and begins at 1A. The letter is always a capital.
V-Scale
The V-Scale dates from 1991, when it was used to grade problems in a guidebook to Hueco Tanks in the US, which is why it is also called the Hueco scale. It starts at V0, has no top, and the number goes up as the problem gets harder.
At the wall and in the app
Some walls sort problems into colour-coded circuits. In the app the V-Scale picker runs from VB to V17 and the Font picker from 3 to 9A. To see how the two line up, read the V grade to Font conversion page.
Source
- British Mountaineering Council, Indoor climbing grades explained: https://www.thebmc.co.uk/en/indoor-climbing-grades-explained
- The Summit Social app, its grade table (17 levels) and grade picker, read in the app's code on 29 October 2026
For all six grade systems side by side, see climbing grades explained.