There are two major categories of impact: 

• Impact within academia: Benefits for research and other academics, and might mean significant advances for the field, or your work being used by other researchers. This type of impact is also sometimes known as 'academic impact' or 'knowledge impact'.
• Impact beyond academia: Benefits arising outside of research; often considered under broad categories such as economy, health, environment, society, culture, depending on the nature of the impact. This type of impact is also sometimes called 'real world impact' or 'societal impact'.

Everyone should have some impact within academia, but only some people will have impact beyond academia. The likelihood of this will depend on your discipline, the disciplines you collaborate with, your career stage, and how translational your work is by nature. 

Remember that impacts come in all shapes and sizes, and it takes time for research to be taken up and used by others and the downstream benefits realised. This is especially true for real world impact.  

Another way to classify impact is in terms of its chronology:

• Retrospective (past) impact: These are benefits that have already happened, such as the uptake of your research findings, or changes that have flowed from that. You should be able to identify it, and evidence it. This type of impact commonly forms part of your track record in funding or prize applications.
• Prospective (future) impact: This is the potential impact that might occur in the future as a result of your work. This type of impact is what is described in the ‘benefits’ or ‘significance’ sections of a research proposal, for example.

Typically, when people talk about research impact they are referring to retrospective impact.