Knowing the CEFR level is necessary, especially if it is one of the requirements you need to fulfill. For example, if you apply for a permit to migrate to the UK, then you need to prove that your English skills are at least on the B1 level by taking the B1 english test. If you want to know your CEFR level, there are several ways that you can do. The best way to find out your CEFR level is to take a well-designed standard test. In English, EFSET is the best choice as it is available for free online and is the first test aligned with CEFR. You need to spend 50 minutes to complete the test and know your CEFR level.
To find your CEFR level in other European languages, all of the most common assessment tests have been aligned with CEFR. You need to take a different test depending on the language. Check with official institutions for languages in Europe, such as Alliance Française for French, Instituto Cervantes for Spanish, or Goethe Institute for German.