DWG vs DXF — Complete Comparison
DWG is Autodesk's native binary format, written and read by AutoCAD itself. DXF is the open interchange format Autodesk publishes so that other software can read the same geometry. Same drawing, two containers: one built for AutoCAD's own use, the other built to be understood by everyone else.
The short version
A DWG holds the drawing in a packed binary structure that only Autodesk fully specifies, so it is compact, exact, and carries everything AutoCAD can author — including objects added by vertical products. A DXF holds the same entities as a stream of numbered group codes and values, usually as plain ASCII text, against a specification Autodesk documents publicly. That makes DXF readable by almost any CAD, CAM or plotting package written in the last thirty years, at the cost of a much larger file and a slightly looser guarantee about the fringes of the drawing.
If the recipient runs AutoCAD or a DWG-compatible package, send DWG. If you do not know what they run, or the file is going into a machine, send DXF.
See the difference for yourself
Reading about group codes is one thing; watching the same drawing render is another. These open in the browser — the file is parsed locally by JavaScript and WebAssembly, nothing is uploaded.
The floor plan carries 46 entities across 7 layers, so you can toggle layers on and off and see how a DXF organises itself. The compare view loads two files with synchronised pan and zoom, which is the fastest way to check what actually survived a DWG to DXF export before you send it on.
DWG vs DXF at a glance
| Property | DWG | DXF |
|---|---|---|
| Full name | Drawing | Drawing Exchange Format |
| Ownership | Autodesk, specification not published; third-party support comes from the Open Design Alliance's reverse-engineered libraries | Autodesk, specification published openly and updated with each release |
| Structure | Bit-packed binary sections with handles, offsets and checksums; later versions compress section data | Group code and value on alternating lines, split into HEADER, CLASSES, TABLES, BLOCKS, ENTITIES and OBJECTS. ASCII by default, with a rarely used binary variant |
| Typical file size | Baseline | Roughly two to five times larger for the same drawing |
| Coordinate precision | Full 64-bit doubles, stored as-is | Decimals written as text; full precision when AutoCAD writes it, but some exporters truncate the digit count |
| What is preserved | Everything the authoring application can create, including custom and proxy objects and dynamic block intelligence | All standard entities, layers, linetypes, text styles, blocks, dimensions and hatch definitions; custom objects survive only as proxy stubs |
| Interoperability | AutoCAD, BricsCAD, ZWCAD, GstarCAD and other ODA-based applications | Effectively universal: CAD, CAM, nesting, GIS, laser and plasma controllers, plotting software, scripting libraries |
| Version tolerance | Low. A reader that does not know the specific DWG version usually cannot open the file at all | High. Unknown group codes and entity types can be skipped, so an old reader still gets the geometry it understands |
| Human readable | No | Yes — you can open it in a text editor, diff it, or generate it from a script |
| Best use case | Live project files, coordination between AutoCAD users, long-term storage of the authored original | Handover to a third party, fabrication and CAM, automated processing, anything where you cannot control the receiving software |
Which should I send my client?
The format question is really a question about the recipient's software. Work through the scenario that matches yours.
- They run AutoCAD, BricsCAD or a similar package. Send DWG, saved down to the release they actually run. A 2018-format file will not open in AutoCAD 2010. If you are unsure, DWG 2013 format is a common middle ground, and it costs nothing to attach a DXF alongside.
- They are a fabricator, laser cutter or CNC shop. Send DXF. Many CAM front ends still ask for R12 or 2000 DXF specifically. Explode the geometry they need to cut, put profiles on their own layer, close your polylines, and strip dimensions and title blocks from the cutting file — those become stray geometry on the bed.
- They use FreeCAD, QCAD, LibreCAD, SketchUp or a GIS package. Send DXF 2000 or later. DWG support in these tools ranges from good to absent, and DXF removes the argument entirely.
- They only need to look at it and comment. Send either, and tell them they can open it in the DWG viewer or DXF viewer in a browser tab with no software to install. Layers, measurement, and arrow or text markup are available there; markup and screenshots can be exported as PNG or PDF.
- The drawing depends on external references. Neither format carries the referenced files. Bind the xrefs or package the set with eTransmit before sending. Note that this viewer does not resolve xrefs either — it shows the host drawing only, so an unbound sheet will look emptier here than it does in AutoCAD.
- The file is the deliverable of record. Send DWG for the authored original, a DXF for anyone outside the AutoCAD ecosystem, and a plotted PDF for the version nobody can argue about.
Why DXF files are so much bigger
Open an ASCII DXF in a text editor and the reason is immediately obvious. There is no packing at all: the format alternates a group code and a value, one per line. A single LINE entity needs its type, its handle, its subclass markers, its layer, and then six separate lines for the two endpoint coordinates — around twenty lines of text before you have drawn anything.
| Stored item | In DWG | In ASCII DXF |
|---|---|---|
| One X coordinate | An 8-byte double, bit-packed against its neighbours | A group code line ("10"), then the number written out in decimal digits, plus two line endings |
| An entity's layer | A handle reference into the layer table | Group code 8 followed by the layer name spelled out on every single entity |
| A hatch or dense polyline | Vertex run encoded compactly | Every vertex expanded into its own code and value pairs |
Two structural effects compound each other. First, numbers stored as text take more room than the same numbers stored as IEEE doubles, and the more decimal places the writer emits the worse it gets. Second, DXF repeats descriptive information — layer names, subclass markers, entity type names — on every entity, where DWG refers back to a table. Later DWG versions also compress their internal sections, while a DXF is written out flat.
That is where the familiar two-to-five-times ratio comes from. It is a range, not a constant: a drawing dominated by a few large blocks stays close to the lower end, while a drawing full of hatching, contours or polyline-heavy survey data sits at the top of it. If the size is a problem in transit, zip the DXF — repetitive text compresses extremely well, and the archive often lands close to the DWG.
Version compatibility, and why DXF degrades more gracefully
Both formats stamp a version code in their first bytes, and the same codes are used for each. The ones you will meet in practice:
| Code | AutoCAD releases |
|---|---|
| AC1014 | R14 |
| AC1015 | 2000, 2000i, 2002 |
| AC1018 | 2004, 2005, 2006 |
| AC1021 | 2007, 2008, 2009 |
| AC1024 | 2010, 2011, 2012 |
| AC1027 | 2013 to 2017 |
| AC1032 | 2018 onwards |
The practical difference is what happens when a reader meets a version it was not built for. DWG is a binary structure of offsets, handles and checksums whose layout changes between versions. A reader that does not implement that exact layout cannot fall back on partial understanding — it refuses the file. This is the source of the familiar "drawing file is not valid" message when a colleague on an older release opens your file, and the reason "save as an earlier version" exists as a command at all.
DXF fails softer. Because the file is a linear sequence of code and value pairs, a reader that encounters an entity type or group code it does not recognise can skip to the next known record and carry on. You may lose a newer entity type, but the walls, the pipework and the text still come through. That tolerance is exactly why DXF remains the format of choice for machine controllers and older shop-floor software that will never be updated.
This viewer reads DWG from R14 through 2026 (AC1014 to AC1032) using a LibreDWG WebAssembly build, and reads ASCII DXF with its own parser. Two honest caveats worth knowing before you rely on a check here: dimensions inside DWG files may not render, which is a known limitation of the parser rather than a problem with your file, and proxy objects created by vertical products such as Civil 3D or Advance Steel will not draw in any viewer that lacks the corresponding object enabler.
Converting between the two
Conversion is routine, and there is no need to pay for it.
- AutoCAD — Save As, then choose the DXF version you need, or run the DXFOUT command. DXFIN and a plain Open handle the reverse.
- ODA File Converter — a free desktop utility from the Open Design Alliance that converts whole folders between DWG and DXF and between versions. The usual choice for batch work.
- BricsCAD, ZWCAD, GstarCAD — read and write both formats natively.
- LibreCAD, QCAD, FreeCAD — free tools that read DXF and can write it back at a chosen version.
To be clear about what this site does: it is a viewer, not a translator. It opens DWG and DXF for inspection, measurement and markup, and its format conversion tools cover 3D meshes (STL, OBJ and glTF), not drawing formats. It can produce a PDF from a DWG, but that PDF is a raster snapshot of the viewport in A4 landscape — useful for a markup or a quick record, not a substitute for a plotted vector sheet.
Frequently Asked Questions
Can I convert DWG to DXF?
Yes, and it is a standard operation rather than a special one. In AutoCAD use Save As and pick a DXF version, or run DXFOUT. BricsCAD, ZWCAD and GstarCAD do the same, and the free ODA File Converter handles whole folders in batch. Geometry, layers, blocks, text and dimensions carry across. What does not carry across is anything that needs a custom object enabler to exist. This site does not perform DWG to DXF conversion; it opens both formats for viewing.
Is DXF lossless?
For everything most drawings contain, yes. Lines, arcs, circles, polylines, splines, text, dimensions, hatch boundaries, layers, linetypes and block definitions all have a documented DXF representation, so a DWG saved as DXF keeps them. The losses appear at the edges: proxy and custom objects from vertical products come across as stubs rather than live objects, dynamic block behaviour may not survive a round trip through third-party software, and coordinate precision can be reduced if the exporting application writes a limited number of decimal places. External references are pointers in both formats, so neither one carries the referenced drawings with it.
Which is better for 3D printing, DWG or DXF?
Neither. Slicers want a triangulated mesh, which means STL, OBJ or 3MF — DWG and DXF are drawing formats and a slicer has nothing to work with. DXF does remain the normal choice for flat-pattern cutting on lasers, waterjets, plasma tables and CNC routers, where the machine wants 2D profiles rather than a mesh. If you are checking a mesh instead, the STL viewer opens binary and ASCII STL, and there is a sample gear to try.
Why is my DXF so large?
Because ASCII DXF is text. Every coordinate is written out in decimal digits with a group code on its own line, and descriptive information such as layer names is repeated on every entity instead of referenced from a table. A DXF is commonly two to five times the size of the equivalent DWG, and hatching, contour lines and dense survey polylines push it towards the upper end. Zipping the file usually recovers most of the difference, since repetitive text compresses well. A binary DXF is smaller than ASCII but is not widely supported — this viewer reads ASCII DXF.
Can I open DWG and DXF files without AutoCAD?
Yes. This site opens DWG from R14 through 2026 and ASCII DXF directly in the browser, with no signup and no upload — the file is read from disk by the browser and stays on your device. Desktop alternatives include DWG TrueView from Autodesk and the various ODA-based free viewers. Our guide on how to open a DWG file covers the options in more detail.
Which DXF version should I save as?
If the recipient has not specified one, DXF 2000 (AC1015) is a safe general-purpose target: old enough to be understood almost everywhere, new enough to include lightweight polylines and modern text objects. Fabrication shops frequently ask for R12 instead, because their CAM software predates everything after it — R12 is simpler and drops some entity types, so check the result before sending. Only reach for a newer version when the recipient needs an entity type that requires it.
Related Guides
Open a DWG or DXF right now
Drop a file into the viewer and inspect layers, measure distances and areas, and mark it up. No signup, no upload — your files stay on your device.
Open Viewer