Levels: 

The Common European Framework divides learners into three broad divisions which can be divided into six levels:

A1 – Breakthrough or beginner
A2 – Waystage or elementary
B1 – Threshold or pre-intermediate
B2 – Vantage or intermediate
C1 – Effective Operational Proficiency or upper intermediate
C2 – Mastery or advanced

Level Descriptions: 

A1  –  Can understand and use familiar everyday expressions and very basic phrases. Can introduce themselves and others and can ask/answer questions about personal details. Can interact in a simple way provided the other person talks slowly and clearly and is prepared to help.
A2  –  Can understand sentences and frequently used expressions related to areas of most immediate relevance (e.g. very basic personal and family information, shopping, local geography, employment). Can describe, in simple terms, aspects of their background, immediate environment, and matters of need.

B1  –  Can understand the main points regularly encountered in work, school, leisure, etc. Can deal with most situations likely to arise whilst traveling in an area where the language is spoken. Can produce simple sentences on topics that are familiar or of personal interest. Can describe experiences, events, & dreams and briefly give explanations for opinions and plans.
B2  –  Can understand the main ideas of complex text on both concrete and abstract topics, including discussions in their field of specialization. Can interact with a degree of fluency that makes regular interaction with native speakers possible without strain for either party. Can produce clear, detailed text on a wide range of subjects and explain a viewpoint on an issue giving the advantages and disadvantages of various options.

C1  –  Can understand a wide range of demanding, longer texts, and recognize implicit meaning. Can express themselves fluently and spontaneously without obvious searching for expressions. Can use language flexibly and effectively for social, academic, and professional purposes. Can produce clear, well-structured, detailed text on complex subjects, showing controlled use of the language.
C2  –  Can understand with ease virtually everything heard or read. Can summarise information from different spoken and written sources, reconstructing arguments in a coherent presentation. Can express themselves spontaneously, very fluently, and precisely, differentiating finer shades of meaning even in the most complex situations.