500 KB STL sample

An STL file of exactly 512,000 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 500 KB sample, test or dummy STL file.

sample-stl-500kb.stl

500 KB512,000 bytes

Download 500 KB STL

Created 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: 4d84dc76eef25c05c0140b8f17db6ff226e7b598df1f8e7079384f3c9319af91
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

An ASCII STL solid, "terrain", of 2,880 triangular facets with unit normals, forming a height field 31 vertices wide. Lines of spaces before the endsolid line, which STL readers skip, bring the file to the exact size.

Facets	2,880
Encoding	ASCII STL
Units	Not specified (model units)
Solids	1

How the file begins

The opening lines of sample-stl-500kb.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

Creates the file in your browser and shows the first 64 KB of it.

Where 500 KB matters

A 512,000-byte file: larger than most API body limits, smaller than most upload limits. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Amazon DynamoDB items	400 KB per item	500 KB cannot be stored as a single item.
Express body parsers	100 KB by default	Rejected unless the limit is raised.
nginx request body	1 MB by default (client_max_body_size)	Accepted with room to spare.

All 500 KB sample files

Use this file for

Checking email size handling
Checking detection of ASCII and binary files
Verifying volume, surface-area and bounding-box calculations

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.

STL format reference

Technical details

File name	sample-stl-500kb.stl
Format	STL (STL 3D model (stereolithography))
Extension	.stl
MIME type	model/stl
Size	512,000 bytes (500 KB)
Kind	Text
Signature	73 6F 6C 69 64
SHA-256	4d84dc76eef25c05c0140b8f17db6ff226e7b598df1f8e7079384f3c9319af91
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-500kb.stl     # Linux
shasum -a 256 sample-stl-500kb.stl # macOS

On Windows, run Get-FileHash sample-stl-500kb.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 500 KB?: Yes. It is 512,000 bytes, which is 500 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 500 KB STL file?: An ASCII STL solid, "terrain", of 2,880 triangular facets with unit normals, forming a height field 31 vertices wide. Lines of spaces before the endsolid line, which STL readers skip, bring the file to the exact size.
Can the sample model be 3D printed?: The sized samples are an open, terrain-like surface with no thickness, intended for testing importers and viewers. The binary cube is a closed, watertight solid that a slicer will accept.

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