AC1021: the AutoCAD 2007 DWG format
AC1021 is the version code of the AutoCAD 2007 DWG format. A drawing that starts with AC1021 was saved by AutoCAD 2007 to 2009, or by another CAD program set to that format. It was the first DWG format to store text as Unicode, so drawings in any alphabet keep their characters.
Open an AC1021 file free Check a file's version
AC1021 at a glance
| Version code | AC1021 |
|---|---|
| Format name | AutoCAD 2007 drawing |
| Saved by | AutoCAD 2007 to 2009 |
| Opens in | AutoCAD 2007 and later |
| Opens in DWG Plotter | Yes, free in your browser |
Which software opens an AC1021 file
Every AutoCAD and AutoCAD LT release from 2007 onwards opens it, as do most other CAD programs that read DWG. AutoCAD 2006 and older cannot open it and show an error instead.
Without AutoCAD, drop the file into the free DWG viewer: you can see every layout, zoom, measure and save it as a PDF. The file is read on your computer and never uploaded.
Opening it in an older AutoCAD
Ask whoever sent the file to save a copy in an older format: Save As, then pick the “AutoCAD 20xx Drawing” file type that matches your release, such as “AutoCAD 2004/LT2004 Drawing (*.dwg)”. If you only need to look at or print the drawing, converting it to PDF is quicker.
Saving a drawing as AC1021
In AutoCAD 2007 or later, choose Save As and set the file type to “AutoCAD 2007/LT2007 Drawing (*.dwg)”. To make it the default, change it under Options, Open and Save. Saving in an older format can simplify objects that format does not support, so keep the original too.
Questions
Which AutoCAD version is AC1021?
It is the AutoCAD 2007 DWG format, used by AutoCAD 2007 to 2009.
Can AutoCAD 2006 open an AC1021 file?
No. AutoCAD 2006 reads only up to AC1018. Save the drawing as “AutoCAD 2004/LT2004 Drawing (*.dwg)”, or view it in a browser instead.
How do I check whether my file is AC1021?
Drop it into the DWG version checker, or open it in a plain text editor: the first six characters are the version code.
Do DXF files use the same AC1021 code?
Yes. A DXF file stores the same code after $ACADVER near the top, so a DXF marked AC1021 is in the 2007 format.
Other DWG versions
AC1032 (2018) · AC1027 (2013) · AC1024 (2010) · AC1018 (2004) · AC1015 (2000) · All versions in one table