Click the "Select File" button above, and choose your S file.
You’ll see a preview, if available.
Click the "Convert file to..." button to extract text information.
Convert S to another file type
To convert S Assembly files to another format, you need GNU Assembler or other Developer software.
Convert a file to S
To convert other file formats to the "Assembly Code" file type, you need software like GNU Assembler or a similar tool.
About S files
The .S file extension is notorious for having multiple, completely unrelated uses. Primarily, it represents Assembly Language Source Code used by the GNU Assembler. These files contain low-level, human-readable programming instructions that map directly to machine code architecture. In the gaming world, .S files act as Microsoft Train Simulator Shape Files, storing proprietary 3D geometry for locomotives and scenery. Strangely, enterprise tools like Siigo accounting software frequently generate .S files that are actually just misnamed PDF or ZIP business documents. The main disadvantage of the .S format is this extreme ambiguity - you cannot easily tell what is inside the file just by looking at the extension. Furthermore, Assembly files are useless to non-programmers, and Train Simulator shape files use an outdated proprietary format that modern 3D software cannot open natively. To make these files usable, they must be analyzed and converted. For code review, convert Assembly files to TXT or PDF. For 3D modeling, Train Simulator shapes should be converted to OBJ or FBX. If you suspect a misnamed business document, drag and drop your file here to analyze and convert it - free, online, and without installing software.
Convert.Guru analyzes your S file, detects the exact format, and lets you read the text inside.
If you want to convert S file to H, HZ, OBJ, FBX, DAE, 3DS, MAX, BLEND, MA, MB, C4D or STL, you can use GNU Assembler or similar software from the "Source Code or 3D Model" category. In the File menu, look for Save As… or Export….
To convert DWG, DAE, X3D, IGES, WRL, JT, SKP, 3DS, 3DM, OBJ, STEP or FBX files to S, try GNU Assembler or another comparable tool in the "Source Code or 3D Model" category.
The S Converter Story
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our S converter.