DWG versions explained
Every few years the DWG format changes. Each version has a code, such as AC1015 or AC1032, written at the very start of the file. This page lists them and explains what they mean for opening a drawing.
DWG version table
| Code | Format name | Used by AutoCAD releases | Opens here |
|---|---|---|---|
| AC1032 | 2018 | 2018 to the current release | Yes |
| AC1027 | 2013 | 2013 to 2017 | Yes |
| AC1024 | 2010 | 2010 to 2012 | Yes |
| AC1021 | 2007 | 2007 to 2009 | Yes |
| AC1018 | 2004 | 2004 to 2006 | Yes |
| AC1015 | 2000 | 2000, 2000i, 2002 | Yes |
| AC1014 | R14 | Release 14 | Yes |
| AC1012 | R13 | Release 13 | Partly |
| AC1009 | R11/R12 | Release 11 and 12 | No |
| AC1006 and lower | R10 and older | 1980s releases | No |
Why the version matters
- Newer files do not open in older software. A drawing saved in the 2018 format will not open in AutoCAD 2017 or in other programs that stop at the 2013 format.
- Old files may not open in new viewers. Many modern tools, including this one, start at R14.
- The format changes less often than the software. AutoCAD 2024 still saves in the 2018 format, so "a 2024 file" is an AC1032 file.
How to find a file's version
- The quick way: drop it into the DWG version checker. It reads only the first few bytes and nothing is uploaded.
- By hand: open the file in a plain text editor. The first six characters are the code, for example AC1027.
- For a DXF file, the version is stored after
$ACADVERnear the top of the file.
How to save a DWG in an older version
In AutoCAD, use Save As and choose an older "AutoCAD 20xx Drawing" type, or set the default in the Open and Save options. Other CAD programs have a similar setting. If you do not have CAD software, ask the sender to do it, or convert the drawing to PDF instead.