25 KB STL sample
An STL file of exactly 25,600 bytes. It is a valid STL 3D model (stereolithography) file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 25 KB sample, test or dummy STL file.
Download
sample-stl-25kb.stl
25 KB25,600 bytes
Download 25 KB STLCreated in your browser in a few seconds, then checked against the SHA-256 checksum. The file is not uploaded anywhere. No sign-up.
- Type
- model/stl
- SHA-256
1e707a6e93af9aee60c1ee8524c8b485a9d97602ab8c77f23bd92bcc4628fc9e- Delivery
- Created in your browser from static generator assets (how it works).
What is in this file
An ASCII STL solid, "terrain", of 144 triangular facets with unit normals, forming a height field 7 vertices wide. Lines of spaces before the endsolid line, which STL readers skip, bring the file to the exact size.
| Facets | 144 |
|---|---|
| Encoding | ASCII STL |
| Units | Not specified (model units) |
| Solids | 1 |
How the file begins
The opening lines of sample-stl-25kb.stl, exactly as they appear in the file.
00000000 73 6f 6c 69 64 20 74 65 72 72 61 69 6e 0a 20 20 |solid terrain. |
00000010 66 61 63 65 74 20 6e 6f 72 6d 61 6c 20 2d 30 2e |facet normal -0.|
00000020 34 34 32 37 20 30 2e 38 30 31 33 20 2d 30 2e 34 |4427 0.8013 -0.4|
00000030 30 32 34 0a 20 20 20 20 6f 75 74 65 72 20 6c 6f |024. outer lo|Preview
Shows the file contents.
Where 25 KB matters
A 25,600-byte file: the size of a small web image or a short document. These are the default limits a file of this size is useful for testing:
| System | Limit | Note |
|---|---|---|
| TCP initial congestion window | About 14.6 KB (10 segments) | 25 KB needs at least two flights of packets on a new connection. |
| Base64 encoding | Adds 33 percent | A 25 KB file becomes about 34 KB inside JSON or an email. |
Use this file for
- Checking thumbnail and icon handling
- Verifying volume, surface-area and bounding-box calculations
- Load-testing viewers with large meshes
Testing notes for STL
- The .stl extension is also used for Windows certificate trust lists, which is why some servers label a 3D model application/vnd.ms-pki.stl.
- A binary file may start with the word "solid" in its free-text header, and many do. Detection has to test whether the file length equals 84 plus 50 bytes for each triangle, not just read the first five bytes.
Technical details
| File name | sample-stl-25kb.stl |
|---|---|
| Format | STL (STL 3D model (stereolithography)) |
| Extension | .stl |
| MIME type | model/stl |
| Size | 25,600 bytes (25 KB) |
| Kind | Text |
| Signature | 73 6F 6C 69 64 |
| SHA-256 | 1e707a6e93af9aee60c1ee8524c8b485a9d97602ab8c77f23bd92bcc4628fc9e |
| Created | 2026-10-23 |
| Validation | See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility. |
| Preview | Available on this page |
| Source | Generated in your browser by this site's generator; not copied from elsewhere |
| Licence | Free to use, modify and redistribute (terms) |
| Category | 3D Models |
Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked
Verify your copy
This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.
sha256sum sample-stl-25kb.stl # Linux
shasum -a 256 sample-stl-25kb.stl # macOSOn Windows, run Get-FileHash sample-stl-25kb.stl -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.
Related files
Questions about this file
- Is this file exactly 25 KB?
- Yes. It is 25,600 bytes, which is 25 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
- What is inside the 25 KB STL file?
- An ASCII STL solid, "terrain", of 144 triangular facets with unit normals, forming a height field 7 vertices wide. Lines of spaces before the endsolid line, which STL readers skip, bring the file to the exact size.
- Are the STL samples ASCII or binary?
- The sized samples are ASCII STL, which can be padded to an exact byte count with blank lines. The curated library adds a binary STL file, a unit cube of 12 triangles.