LingQ simply calculates your level by counting the number of known words. So it is only a rough calculation. Only your passive vocabulary is considered. Your ability to speak and write, and your use of grammar is not considered like in the CEFRL.
I think like Skyblueteapot that LingQ grades to early learners as Advanced 1 or Advanced 2.
Here you can read about it: http://www.lingq.com/help/avatar/
For example I would consider my level of English as B2. But LingQ grade me as Advanced 1, and I'm not far from Advanced 2 on LingQ.