Hi Hugh,
You have to mark the layer>Save As
Choose an UTM projection so you can calculate in m2 and km2.
Close the original layer and zoom to the new UTM layer - This only for 
visualizing - not for any function..

Click on Attribute table>Fieldcalculator
Either make a new field or update an exsisting field.

I´ve made a small video to show how to. - Sorry I´m using in danish version ;-)
http://screencast.com/t/ZQJyb6zj

Regards
Lene Fischer
________________________________
Fra: [email protected] [[email protected]] på 
vegne af Wenban-Smith [[email protected]]
Sendt: 13. september 2013 18:13
Til: [email protected]
Emne: [Qgis-user] Query re: Area measures

My QGIS project uses a .shp file of 179 districts in Tanzania. I wish to know 
the area of each district in sq km but the Geometry-$area function (in the 
field calculator of the Attributes table) only reports areas in decimal degrees 
(whereas the individual area measuring tool from the toolbar reports sq km but 
is tedious to use and not precise). It appears looking under Settings/Project 
Properties [General tab] that it is possible to convert to meters only when CRS 
transformation is disabled but there is no guidance how to do this (nor why 
this should be necessary). I have tried converting the CRS from Arc 1960 to one 
the UTM ones but this did not help.

Grateful for any advice more experienced users can offer.

Hugh W-S

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