There are so many different standardised tests available to test your English skills: the Cambridge certificates, TOEIC, TOEFL, IELTS, BULATS and, here in Japan, the Eiken/STEP test.
For a lot of people, these tests are pointless. If you need the certificate to get a job or a college place, go for it. If not, read on.
Tests You Can Do By Yourself
Get an internet article, book, newspaper or other document that you may be interested in.
How much can you read and understand without using a dictionary? How often do you need to use a dictionary?
Watch a DVD without subtitles.
How much can you understand in a 10-minute scene? A whole episode/movie?
Tests You Can Do With Others
Write something on social media or write an email.
Do you get replies? Do they state that your English is correct? Do the replies connect with what you meant to say?
Have a conversation, face-to-face or on the telephone. (The telephone may be expensive but it is a lot cheaper than any of the standardised tests above). Some places to call may be tourist information offices in places you’d like to visit.
Can you be understood? Can you understand the person speaking to you? How easy or difficult is it?