As a guideline I use CEFR - The Common European Framework of Reference for Languages (CEFR), an international standard for describing language ability.
While learning a foreign language, it is important to determine what level you are at and what learning goals are relevant for the development of your language skills.
What is CEFR?
CEFR is an international standard for describing language ability. It describes language ability on a six-point scale, from A1 for beginners, up to C2 for those who have mastered a language.
Read more about CEFR here Council of Europe
English (UK) 
Dansk