I'm calculating field of various features in my shapefile using QGis.
I'm getting some sample length as
I want to know in what unit (eg: meters, km etc) is the above value ?
This is a measurement of whatever map units are specified in your project properties or CRS.
"To set project properties click "[Settings > Project Properties]" in the main menu. The "Project Properties" window will appear. Click on the "[General]" tab and set Project Title and Map Units."