gistfile1.diff

diff --git a/src/core/qgsdistancearea.cpp b/src/core/qgsdistancearea.cpp
index 269e0ae..bbcb5d5 100644
@@ -808,14 +808,22 @@ QString QgsDistanceArea::textUnit( double value, int decimals, QGis::UnitType u,
     case QGis::Feet:
       if ( isArea )
       {
-        if ( keepBaseUnit  || qAbs( value ) <= ( 528.0*528.0 ) )
+        if ( keepBaseUnit  || qAbs( value ) <= 0.5*43560.0 )
         {
+          // < 0.5 acre show sq ft
           unitLabel = QObject::tr( " sq ft" );
         }
+        else if ( qAbs( value ) <= 0.5*5280.0*5280.0 )
+        {
+          // < 0.5 sq mile show acre
+          unitLabel = QObject::tr( " acre" );
+          value /= 43560.0;
+        }
         else
         {
+          // above 0.5 acre show sq mi
           unitLabel = QObject::tr( " sq mile" );
-          value = value / ( 5280.0 * 5280.0 );
+          value /= 5280.0 * 5280.0;
         }
       }
       else

• so you're removing if area is <= .01 sq miles and swapping for if area if <= .5 acres do sq ft
• else if area <= 1/2 a sq mile do acres
• else do square miles

Calculation wise it looks fine. I'm not really sure what most ends users expect other than to be able to toggle between acres/miles easily.