Here on italki there's only the possibility to do the Oxford Online Placement Test for 10$. They don't have tests for other languages and every user can decide themselves what level they display. Always take the levels of others with a grain of salt. Some display five mother tongues. Or they set English as mother tongue but are intermediate at best.

It is a self-evaulation.  You set the level in your profile.

Hey Michelle,

There are several different ways you can find this out. There are many accredited testing centres dependant on the language you are learning. I gather you are wanting to gauge your Spanish, so a future goal could be to take the DELE by the  cervantes institute. I believe there is another, but I cannot remember it at present. These are paid for, so it is best to aim for them once you have already amassed a solid foundation in the language.

It is also worth reading up on the different possibilities as some of these certificates "expire" after a few years, others are with you for life.I am not that up on the Spanish certificates and testing centres as I only started learning Spanish properly in November and have had a month off already. However, I would state that I am a high A1, possibly a very low A2 after having completed 60 lessons of Pimsleur, foundation Michel Thomas, 63 hours spoken Spanish with a private teacher, two books read, roughly 1600 words "learnt", etc. If that helps you gauge your level. For my German I simply passed the relevant test, though there are more options available for German TestDAF and TELC being the main ones. 

For now, if you are starting out in Spanish (I am not sure if the language is new to you, or you simply wanted to wait before putting your level in after some confirmation) either way: https://dialangweb.lancaster.ac.uk/ This website is widely used in the polyglot/language enthusiast community to get a rough idea of level. It scores you based on the CEFR (Common European Framework of Reference for Languages) 

https://www.laits.utexas.edu/fi/sites/laits.utexas.edu.fi/files/Self%20Assessment%20Checklist%20European.pdf ;
From what I have seen here, some people definitely just guess their level.