The definitive ranking of the 30 best universities in the world

Picking the right university is one of the first big decisions of adulthood.

To help, QS has ranked universities since 2013 using a methodology that evaluates academic reputation, employer reputation, student to faculty ratio as well as international reputation.

Using a points system, QS then rates the university out of 100.

The latest rankings were published on Tuesday and can be found on the QS website.

It hasn't been a great year for British universities. Thirty eight of the UK's 48 universities in top 400 have dropped down the rankings this year, with Cambridge falling out of the top three.

Political uncertainty over immigration reform and problems with long-term funding, could have affected the UK universities' performance, said Ben Sowter, head of research at QS, according to a report in The Telegraph.

Most of the top 30 are in the US, but here's the definitive ranking: