How to Change FreeCAD Units to Imperial
This guide explains how to switch the default unit system in FreeCAD from the standard metric system to imperial units. By adjusting the application's global preferences, you can configure FreeCAD to automatically display, input, and calculate all dimensions in inches, feet, and pounds across your workbenches and future projects without altering the underlying geometry of your designs.
Step-by-Step Instructions
- Open the Preferences Menu
- On Windows and Linux: Click Edit in the top menu bar, then select Preferences.
- On macOS: Click FreeCAD in the top menu bar, then
select Preferences (or press
Cmd + ,).
- Navigate to the Units Tab
- In the left-hand sidebar of the Preferences window, select the General category (represented by a gear icon).
- Click on the Units tab located at the top of the General settings pane.
- Select Your Desired Imperial Unit System
- Locate the dropdown menu labeled User system. By default, it is set to Standard (mm/kg/s/degree).
- Click the dropdown and choose one of the imperial options based on
your workflow:
- US customary (in/lb): Uses inches and pounds, displaying fractions where applicable.
- Imperial decimal (in/lb): Uses inches and pounds,
displaying values strictly in decimal format (e.g.,
1.250 in). - Building US (ft-in/lb): Ideal for architectural and
woodworking models, displaying dimensions in feet and fractional inches
(e.g.,
3′-6 1/2″).
- Adjust Unit Precision (Optional)
- In the same tab, you can set the Number of decimals
to define how many decimal places FreeCAD displays in input fields and
properties. A value of
2to4is typical for engineering and modeling.
- In the same tab, you can set the Number of decimals
to define how many decimal places FreeCAD displays in input fields and
properties. A value of
- Apply and Save
- Click the Apply button at the bottom right.
- Click OK to close the Preferences window.
Note on Existing Projects
Changing the unit system is purely visual. FreeCAD stores values internally using consistent standard units, so changing your preferences will immediately convert and display existing dimensions in your selected imperial format without distorting or scaling your models.