> For the complete documentation index, see [llms.txt](https://docs.moasure.com/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.moasure.com/en/moasure-lx1/settings/display-options/area-calculation-method.md).
# Area Calculation Method
Choose how the area of your LX1 floor plan is calculated and displayed.
Open **Settings**, tap **Display Options**, then tap **Area Calculation**.
Choose from:
* **Gross External Area** — area measured to the outside face of all external walls. Also called Building Footprint.
* **Gross Internal Area** — area measured to the internal faces of the external walls, excluding wall thickness. Includes internal walls and features.
* **Net Internal Area** — usable floor space inside the building. Excludes external walls, internal walls and structural elements.
Select the calculation method you want to use, then tap **Save**.
The area displayed on your floor plan will update using the selected calculation method.
### Gross External Area
Gross External Area (GEA), also referred to as the **Building Footprint**, calculates the area to the outside face of the external walls.
To calculate GEA, LX1 uses the **Exterior Wall Thickness** assigned to the floor plan.
#### Set the Default Exterior Wall Thickness
You can set a default Exterior Wall Thickness to be used for future measurements.
To set or change the default:
1. Open **Settings**.
2. Tap **Measuring Options**.
3. Tap **Exterior Wall Thickness**.
4. Enter the appropriate exterior wall thickness for the property.
5. Tap **Save**.
This value will be used as the default Exterior Wall Thickness for new measurements.
#### Change the Exterior Wall Thickness for an Existing Measurement
If you need to change the Exterior Wall Thickness for an existing floor plan, open the measurement and tap **Edit** and select **Exterior Wall Thickness** from the ribbon.
Enter the appropriate wall thickness for the property. The Area will update using the new value.
{% hint style="info" %}
**Note:** Changing the Exterior Wall Thickness in **Settings** only changes the default for future measurements. To change the Exterior Wall Thickness for an existing measurement, use the option in the ribbon.
{% endhint %}
{% hint style="info" %}
**Note:** Gross External Area currently uses the assigned Exterior Wall Thickness rather than individually measured exterior wall thicknesses.
{% endhint %}
---
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