The Calculate Geometry tool is disabled for certain fields

Description

When attempting to calculate geometry for certain fields in an attribute table, the Calculate Geometry tool is disabled.

Cause

The selected field is an inherent field of the feature class managed by the geodatabase. For example, in a polygon feature class, there are four fields that are unavailable for editing: OBJECTID, Shape, SHAPE_LENGTH, and SHAPE_AREA.

When a new line feature class is created, an additional field is automatically created to record the length of the line. Likewise, when a new polygon feature class is created, two additional fields are automatically created to record the length (perimeter) and the area for each polygon feature. These are required fields and the properties cannot be modified.

Solution or Workaround

To perform the Calculate Geometry operation, add a new field to the existing attribute table. The new field automatically records the properties of the feature. Use the following procedure to create a new field and use the Calculate Geometry tool:

1. Open ArcMap. In the Table Of Contents pane, right-click the desired feature class. Click Open Attribute Table.
2. In the attribute table, click Table Options > Add Field.

Note:
Ensure all previous editing is saved to enable the Add Field option in the Table Options drop-down list. In the Editor window, click the Editor drop-down, and click Save Edits.

3. Under Type, select Double as the data type to allow possible decimal points.

4. Click OK.
5. Right-click the new field header, and click Calculate Geometry.

6. In the Calculate Geometry window, specify the desired calculate geometry Property, the Coordinate system, and the desired measurement Units, and click OK.