The Big-Five model of personality traits is the most popular model of personality traits among personality psychologists. Take this 300-item personality test to see how you score on the Big Five personality dimensions, as well as 30 more specific personality facets.
If you just want to learn your scores on the Big Five personality dimensions, you can take the shorter, 44-item Big Five Inventory. However, the Big Five Inventory will not give you results for the 30 more specific personality facets.
The IPIP-300 gives the exact same results page as the IPIP-120. However, because it asks more questions, it can estimate your personality traits with far greater precision.
The IPIP-300 is an in-depth personality test that is very similar to the popular NEO-PI-R. The IPIP-300 is widely used by real personality psychologists to assess personality traits.