The CEFR (Common European Framework of Reference for Languages) offers a good written guideline of different language levels where you can judge for yourself what you level might be (the CEFR is also used by italki in your profile). And then there are plenty of websites where you can get at least a rough estimate of your level for free, like here from the British Council: https://learnenglish.britishcouncil.org/en/content
Obviously those free online tests won't be able to judge your level very well in speaking, for example, because the tests are automatic.
I know I'm basic because many errors.
i am here to improve.
And I will!