The rating systems shown in this table compare the main rating systems that are used in the Climbing World. There are many more rating systems, but we will use this one for now.
UIAA Rating System
The Union Internationale des Associations d'Alpinisme (UIAA) rating scale is used mostly in Western Germany and Austria.
The French Rating System
The French Rating System is slowly becoming the international standard, at least for comparing really hard climbs. It is used in France, as well as in Spain and Italy.
The British Grading System
People in Britain have two different ratings: an adjectival grading and a technical grading. The adjectival grading says something about the overall difficulty of the climb. On the other hand, the technical grading shows something about the most difficult move of the climb.
For instance, an easy climb with a difficult move would have a relatively low adjectival grading with a high technical rating (like E4/6c). A sustained climb with long runouts and poor pro - a real British climb - but no real difficult technical moves has a high adjectival rating with a low technical rating (like E7/6b).
The Yosemite Decimal System is the North American rating system. The first number in the YDS designates the class of the climb (always "5" for free climbs), while the second number defines the difficulty.
See related climbing gear:
Keep in mind that there are many rating tables. The one above is an example. You can also choose what Rating System you will use based on your preferences.