Cambridge English exams qualifications are recognized globally and are officially accepted by thousands of universities, employers and governments. http://www.cambridgeesol.org/index.html
IELTS is recognized by more than 7,000 institutions in over 135 countries. Over 1.7 million IELTS tests were taken last year.
The TOEFL test is recognized by more than 8,500 colleges, universities and agencies in more than 130 countries. www.ets.org/toefl