Why Can’t I Change Line Thickness in AutoCAD?

In AutoCAD, there might be instances where you find yourself wondering why you can’t change the line thickness of certain objects. This can be a frustrating experience, especially when you need to create drawings with varying line weights for clarity and emphasis. In this article, we will explore some common reasons why this issue might occur and how to troubleshoot it.

1. Layer Properties

One possible reason why you can’t change the line thickness is due to the layer properties.

AutoCAD has a feature called “layer properties” that allows you to assign specific properties, such as line weight, color, and linetype, to different layers. If the object you are trying to modify is on a layer with a locked or fixed line weight setting, it will prevent any changes from being applied.

To check and modify the layer properties:

  1. Select the object or objects whose line thickness you want to change.
  2. Open the “Layer Properties Manager” by typing “LA” in the command line or by clicking on the “Layer Properties” button in the ribbon.
  3. In the Layer Properties Manager, locate and select the layer containing your objects.
  4. Adjust the “Lineweight” value for that layer to your desired thickness.

2. Object Properties

Another reason for not being able to change line thickness is due to specific object properties overriding any global settings. AutoCAD allows you to assign individual lineweight values directly to objects, which takes precedence over layer settings.

To modify object properties:

  1. Select the object or objects whose line thickness you want to change.
  2. Right-click on one of the selected objects and choose “Properties” from the context menu.
  3. In the Properties palette, navigate to the “Lineweight” property.
  4. Change the value to your desired thickness.

3. Plot Style

The plot style in AutoCAD determines how objects are printed or plotted.

If you are experiencing difficulties changing line thickness, it might be due to the plot style assigned to your drawing. Some plot styles have specific settings that control line weights and can override any changes made at the layer or object level.

To modify the plot style:

  1. Type “PAGESETUP” in the command line and press Enter.
  2. In the Page Setup Manager dialog box, select your desired page setup.
  3. Click on the “Modify” button.
  4. In the Plot Style Table Editor dialog box, make sure that the “Plot Style” column is set to “Use Object Color”.
  5. Click on OK to save your changes.

4. Drawing Scale

Sometimes, when working with a small drawing scale, line weights may appear thicker than expected due to scaling factors. This can give the impression that you can’t change line thickness when, in fact, it is being affected by scale settings.

To adjust drawing scale:

  1. Type “SCALELISTEDIT” in the command line and press Enter.
  2. In the Scale List Edit dialog box, select your desired scale from the list of scales being used in your drawing.
  3. Click on Modify and adjust the value as needed for accurate representation of line weights at that particular scale.


When you find yourself unable to change line thickness in AutoCAD, consider checking the layer properties, object properties, plot style, and drawing scale. By understanding and troubleshooting these factors, you can regain control over line weights and create drawings that meet your specific requirements.