Both indoor and outdoor climbs are rated on difficulty using grades, and different styles are graded in different ways. There are French grades, adjectival grades, technical grades and combined grades.
French grades – Most walls are rated using French grades, so these will probably be the first type you’ll come across as a newcomer. French grades are really simple. They start at 1 and increase relative to difficulty. Once you get to 4, subgrades are introduced, with 4a & 4b. There’s also 4a+, which sits between 4a and 4b.
French grades are as follows: 4 , 4+ , 5 , 5+ , 6a , 6a+ , 6b , 6b+ , 6c , 6c+ , 7a , 7a+ , etc.
Adjectival grades – Outdoor trad routes will often be given what’s known as an ‘adjectival grade’ to tell you how hard it is overall. The grades are: Moderate (M), Difficult (D), Hard Difficult (HD), Very Difficult (VD), Hard Very Difficult (HVD), Severe (S), Hard Severe (HS), Very Severe (VS), Hard Very Severe (HVS) and Extremely Severe (E), which is split into E1, E2 & E3. Adjectival grades are based on a range of factors, including technical difficulty, rock quality and strenuousness.
Technical grades – While the adjectival grade takes into account lots of different difficulty factors, the technical grade is based solely on the single hardest move on the route. Technical grades run like this: 4a, 4b, 4c, 5a, 5b, 5c and so on.
Combined grades – As if that wasn’t complicated enough, British trad routes are often graded using both the adjectival and technical grades. It’s easiest to think of these grades in two parts. The adjectival grade will describe the overall difficulty of the route, taking into all factors (strenuousness, rock quality etc.), with the technical grade included so you know the technical difficulty of the route’s hardest move.