What are the differences between KPI and KRA in terms of performance management?

1. Key result areas are the main goals that an employee needs to accomplish. Example of  an HR related KRA (Recruitment, Training & Development, Employee Retention). 
2. Key performance indicators are measurable indicators used to evaluate your performance level.  Every Key Result Areas must have at least one KPI.Example of a Training & Development KPI (Training Hrs per Employee / Year).

Key Performance Indicator: Objective oriented.

Key Result Area: Ouput oriented.

KRA(Key Result Areas ) are the main goals that need to be accomplished. KPI (Key Performance Indicators ) are measurable indicators used to evaluate your performance level. Every Key Result Areas must have at least one KPI. Total number of KPI's should be8-10 items. Weight age of each KPI will be defined.Total weight age will be100. 

A performance indicator or key performance indicator (KPI) is a type of performance measurement.[1] KPIs evaluate the success of an organization or of a particular activity in which it engages. Often success is simply the repeated, periodic achievement of some levels of operational goal (e.g. zero defects,10/10 customer satisfaction, etc.), and sometimes success is defined in terms of making progress toward strategic goals,.[2] Accordingly, choosing the right KPIs relies upon a good understanding of what is important to the organization

KRA :

Key Result Areas are the main goals that an employee needs to accomplish.

KPI :

Key Performance Indicators are measurable indicators used to evaluate your performance level. Every Key Result Areas must have at least one KPI.

to give an HR example - if one of the KRA's are recruitment as per man power plan or a number say100 in a year than KPI will boil down to cycle time for recruitment, acceptance of offer Vs joining, cost of recruitment per employee - the KPI's can be fine tuned to make them more efficient & effective which in turn will impact the achievement of the KRA

Key Performance Indicator.

Key Result Area.

Key result areas 

Key performance indicators 

Key Result Areas refer to general areas of outputs or outcomes for which the department’s role is responsible.

Key Performance Indicators, also known as KPI or Key Success Indicators (KSI), help an organization define and measure progress toward organizational goals.