CEFR- International English Standards

The Common European Framework of Reference for Languages (CEFR) is exactly what its title says it is: a framework of reference. 

What the CEFR can do is to stand as a central point of reference.

The CEFR describes language ability on a scale of levels from A1  for beginners up to C2 for those who have mastered a language. 

The CEFR describes foreign language proficiency at six levels: A1 and A2, B1 and B2, C1 and C2. It also defines three ‘plus’ levels  (A2+, B1+, B2+). 

This is the CEFR global scale:

Cambridge ESOL (English for Speakers of Other 
Languages) exams integrate the CEFR standards. 
The equivalences are:

CEFR A2: KET (Key English Test)

CEFR B1: PET (Preliminary English Test)

CEFR B2: FCE (First Certificate in English)

CEFR C1: CAE (Certificate in Advanced English). 

CEFR C2: CPE (Certificate of Proficiency in English).