25 KB BIN sample file

A BIN file of exactly 25,600 bytes. It is a valid Binary test file file, generated for this site and checked with an independent parser.

sample-bin-25kb.bin

25 KB25,600 bytes

Download 25 KB BIN

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Type: application/octet-stream
SHA-256: 0086ade48bf571d6622b65184ea571fb2acdfeb6ec4abe4da8eb6b7fa1efa2e0
Direct URL: https://sampletestfiles.com/downloads/bin/sample-bin-25kb.bin

What is in this file

25,600 pseudo-random bytes from a seeded generator, so every build of the file is identical and compression cannot shrink it.

Content	Pseudo-random bytes
Compressible	No
Structure	None

First bytes of the file

The first 64 bytes of sample-bin-25kb.bin as a hex dump: offset, bytes, then the same bytes as text.

00000000  8c 1e 4d 5c a6 a3 42 44 9c be 52 f7 9a 8e 07 e6  |..M\..BD..R.....|
00000010  de 91 95 44 61 de 2e af 0c 7a 0f 71 8c ff 7d 67  |...Da....z.q..}g|
00000020  46 bc 65 44 71 7e 8d 8c 37 a8 e6 15 1a ea b9 ff  |F.eDq~..7.......|
00000030  28 e5 94 f2 d0 65 53 74 dc 68 35 2e 6f f1 b8 db  |(....eSt.h5.o...|

Preview

BIN files cannot be shown in a browser. Download the file and open it with curl, wget and browser download managers.

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.

All 25 KB sample files

Use this file for

Testing avatar and logo uploads
Verifying checksums after transfer
Measuring download and upload throughput

Testing notes for BIN

Because application/octet-stream says nothing about content, strict upload filters reject these files. That is itself a useful test.
A file of zeros, as produced by many quick commands, compresses to almost nothing, which makes transfers look far faster than they are.

BIN format reference

Technical details

File name	sample-bin-25kb.bin
Format	BIN (Binary test file)
Extension	.bin
MIME type	application/octet-stream
Size	25,600 bytes (25 KB)
Kind	Binary
SHA-256	0086ade48bf571d6622b65184ea571fb2acdfeb6ec4abe4da8eb6b7fa1efa2e0
Created	2026-10-10
Validation	Exact size, signature bytes and structure checked when the file was generated
Preview	Not available for this format; details only
Source	Generated for this site; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Testing

Validated for expected format and integrity. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Download from the command line and verify

Fetch the file with curl, then compare its checksum with the SHA-256 value above.

curl -o sample-bin-25kb.bin 'https://sampletestfiles.com/downloads/bin/sample-bin-25kb.bin'
sha256sum sample-bin-25kb.bin     # Linux
shasum -a 256 sample-bin-25kb.bin # macOS

On Windows, run Get-FileHash sample-bin-25kb.bin -Algorithm SHA256 in PowerShell. A matching value proves that the download is complete and unaltered.

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 BIN file?: 25,600 pseudo-random bytes from a seeded generator, so every build of the file is identical and compression cannot shrink it.
Why not use a file full of zeros?: Zeros compress to nearly nothing, so any compression between server and client hides the true transfer size. Random bytes do not.

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