These are what you can do to make your AutoCAD files smaller

When working with AutoCAD, sometimes you can see that your files get unusually large. It may slow your system down and it might crash the system. You might want to try to reduce the file size.

Other reason why you want to reduce the file size is because you need to send it as attachment or upload it.

So let’s see what we can do to reduce AutoCAD file size.


Audit doesn’t reduce file size. But it is recommended to do file audit before we continue with other process. It will maintain the drawing integrity and fix errors that might prevent us to remove unnecessary objects.

If you are not familiar with audit, you can run it by typing AUDIT at command prompt then press enter.

Or you can access AutoCAD menu (the big red A) > Drawing utilities > Audit.



After you audit the drawing you can run PURGE. You can type PURGE at command line then press enter. AutoCAD will open a dialog box like below.

As you can see in the list, you can purge or remove unused objects. Block definitions, styles, materials and layers.

Remember, if you still need to use them, do not purge all items.


Purge regapps

Regapps stands for registered applications. To purge regapps you need to type –PURGE (with the – prefix) then enter. Type R for regapps then enter again.

In many cases, purge regapps can significantly reduce the file size.

If you want to know more about regapps, check this post by Donnie Gladfelter: Ditch excess RegApps & Speed Up Your Drawings.


Purge removes unused objects. WBLOCK works differently. With WBLOCK you choose objects that you need and save it to a new clean file. So you left the excess in the origin file.

You can activate WBLOCK by typing WBLOCK then press enter. Using this command is very similar to creating block. This command was originally for create block as external DWG, but we can use it for this purpose as well.

I would recommend you to select only objects you want to write to new file. Do not type ALL when AutoCAD ask you to select objects.


AutoCAD issues related to file size

If you have done all above but you think your file is still unnecessarily large, it might be because there issues with your file. There are also some known issues related to this bloated file size. Some famous issues are:

Scale list issue

This issue was found in AutoCAD 2008, when Autodesk first introduce annotation scaling. You can have so many scale list in your drawing, especially if you work with reference file.

You can clean up the scale list by using available clean up utility.

You can download scale list clean up utility for AutoCAD 2014 here.

DGN Lineweight

Another issue that can cause DWG file to increase file size is because DGN linetype issue. This can happen if you work with DWG that contains DGN linetype.

There is hotfix available for this issue, and the hotfix also provides clean up utility.

You can download DGN hotfix here.

Remember to read the readme file because you need to manually copy files before you can run the utilities.

Other optimization

Thank you for all emails and comment I received after I published this article. These are some more things that you can do:

Tips from Jacob Dunkelman:

  • Delete layer filter, on same cases, after DLF the file size was reduced to 5% from its original size
  • Delete groups. Mainly the unnamed groups. Some add-on are heavy users of unnamed groups
  • Delete layer state managers
  • Detach unreferenced XREFs and IMAGES

Tips from Billy Stang:

Use the “overkill” command to reduce file size and clean up a drawing.

Tips from Tawfik Shehata:

Use of blocks for repeated instance of objects.

Remove unused annotative scales from objects. To prevent applying unnecessary annotative scales to objects, make sure that ANNOALLVISIBLE is set to 0 and ANNOAUTOSCALE is set to -4 these 2 system variables are set per layout/model.

How big a DWG should be?

A drawing file may be large if it’s a complex drawing. Especially if you work with 3D model. However, if your drawing is quite simple but the file size is more than 10 MB then something might be wrong.

If you have done all above procedure but your file is still large, then it might be because the complexity of your drawing.

Are there any other issue that you know can increase the file size? Or is there any other method that we can do to reduce file size?

Share your experience with us here!


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  1. Florentina says

    What worked for me in dealing with increased in size AutoCAD files dues to DGN,
    was to use DXFOUT and DXFIN twice for each file.
    It decreased from 18MB to 11MB and to approx 250KB after the second DXFIN.

  2. ronel pabico says

    aside from purge command, we can use also OVERKILL command to get rid of those overlapping and or lines on top of another line

  3. fernando says

    Hi, firstly thank you for your advices, I have a file which is quite simple and it is 86 mb, is very heavy but it is just a layout of a house, I guess the fact that I have imported from Revit might cause the file is that heavy.
    I have tried all your advices but still nothing, I have a hundred of different type of lines which I am not able to delete.
    Is there any other way to clean files, specially from Revit.

  4. Cornel Gherasim says

    Deleting eventual overlapping entities and unused dictionaries, using lightweight polylines instead of old polylines (check the system variable PLINETYPE) and avoiding hatch scales resulting in a too high density of the pattern, might help keeping a small file size.

  5. Massimo Corradi says

    There is a very good (and free) cleanup tool from Ajilal Vijayan in the Exchange Apps, search for "Drawing Purge". It purges DGN linetypes, RegApps, Scales among other things, and it works also without opening drawings in editor.

  6. adrian says

    How about using the command Dfxout. After doing it use purge and audit command for dxf file. Then save, overwrite the original Dwg file. it may help this approach which file has 10mb. hope it helps.

  7. Tawfik Shehata says

    A smart use of blocks while creating the drawing can significantly reduce the file size, whenever possible, create blocks of any repeated instance of objects even if it's only 2 lines then bigger blocks of any repeated combination of smaller blocks, and so on.

    Also remove unused annotative scales from objects. To prevent applying unnecessary annotative scales to objects, make sure that ANNOALLVISIBLE is set to 0 and ANNOAUTOSCALE is set to -4 these 2 system variables are set per layout/model.