Calculate Polygon Area in QGIS

How to Calculate Area of a Polygon in QGIS

Updated on:

June 8, 2026

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Use this interactive demo to learn how to measure polygon area using QGIS Field Calculator.

Quick summary

In QGIS, you can calculate the area of a polygon by using the Field Calculator to create a new attribute field with the built-in $area expression. This method stores the computed area directly in the layer's attribute table, making spatial analysis fast and repeatable.

Steps

Right-click your polygon layer and select Open Attribute Table.
Click the Field Calculator icon in the dialog box.
Check Create a new field to set up a new attribute column.
Set the Field name to Area and the Field type to Decimal number (real).
In the expression box, type the Area formula $area.
Click OK to run the calculation.
Confirm that the area of the polygon has been successfully calculated and saved to the attribute table.

📌 Why this matters

QGIS is a free, open-source GIS platform widely used by urban planners, environmental scientists, and surveyors who need to perform accurate geospatial analysis without expensive software licenses. The ability to calculate polygon area directly within the attribute table using the Field Calculator and the $area expression is a fundamental skill that enables users to quantify land coverage, measure site extents, and prepare data for reporting. This workflow is entirely non-destructive — it stores computed values as a new field — making it easy to update or audit results as data changes. Mastering this technique in QGIS unlocks a wide range of downstream spatial analyses, from zoning assessments to environmental impact studies.

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