[Qgis-user] Assistance with Calculating Polygon Area in Hectares (EPSG:25832)

[Andrea Giudiceandrea]

> Phil Wyatt phil at wyatt-family.com
> Wed Dec 17 23:39:25 PST 2025
> Make sure the field is Decimal with a precision of 3

Hi Phil,
the result of the expression

round( $area / 10000, 2) || ' ha'

is a string, thus the field type set in the Field Calculator should 
actually be Text, not Decimal, in order to correctly store the result of 
such expression.

 > Christoffer Toft Hviid Jensen cth at patriotisk.dk
 > Wed Dec 17 23:22:30 PST 2025> I use this expression round( $area / 
10000, 2) || ' ha'  in the calculator box through the attributtable.

Hi Christoffer, the function round() obviously returns 0 if the first 
argument is equal or less than 0.004 and the second argument is set to 2.
So the expression will return '0 ha' if $area / 10000 is equal or less 
than 0.004 (ie $area is equal or less 40).
Are you sure that $area / 10000 is greater than 0.004 (ie $area is 
grater than 40) for the given features?

Moreover, the unit of measure of the value returned by the function 
$area (which calculates the Ellipsoidal area of a geometry) is the unit 
of measure set in Project Properties -> General -> Measurements -> Units 
for area measurements.
Since you are using the formula $area / 10000 in your expression, then 
the unit of measure of the value returned by the function $area should 
be square meters in order for the formula $area / 10000 to return a 
value in hectares.
Are you sure such settings is set to 'Square Meters'?

Regards.

Andrea