20 MB TXT sample file

A TXT file of exactly 20,971,520 bytes. It is a valid Plain text file, generated for this site and checked with an independent parser. Use it wherever you need a 20 MB sample, test or dummy TXT file.

sample-txt-20mb.txt

20 MB20,971,520 bytes

Download 20 MB TXT

Created in your browser in a few seconds, then checked against the SHA-256 checksum. No sign-up.

Type: text/plain
SHA-256: 3913f245aa8fa5b964ef74e4b68876534b722b2336d296178eab652145217b69
Delivery: Created in your browser. Files of 2 MB and more have no direct URL (why).

What is in this file

206,358 numbered lines of plain English text, each prefixed with its line number and starting byte offset so truncation is easy to spot. A closing rule of "=" characters brings the file to the exact size.

Numbered lines	206,358
Encoding	UTF-8 (ASCII characters only)
Line endings	LF (Unix)

How the file begins

The opening lines of sample-txt-20mb.txt, exactly as they appear in the file.

SampleTestFiles sample text file (20 MB)
Encoding: ASCII, which is also valid UTF-8. Line endings: LF.
Each numbered line starts with its line number and the byte offset at which it begins.

0000001 000000191 This sample file exists so that software can be tested with realistic input.
0000002 000000286 Every line in this document was generated by a script and describes nothing confidential.
0000003 000000394 Use it to check that uploads, downloads and parsers behave the way you expect.
0000004 000000491 The file was built to an exact byte count, which makes size limits easy to verify.
0000005 000000592 If the last line of this file is missing, the transfer was cut short.
0000006 000000680 A good test fixture is boring, predictable and identical every time it is downloaded.
0000007 000000784 Compare the checksum published on the download page with the one you compute locally.

Preview

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

Where 20 MB matters

A 20,971,520-byte file: right at the default attachment limit of Outlook, and just under the 25 MB ceilings of Gmail and GitHub web uploads. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Microsoft Outlook	20 MB of attachments by default for internet mail accounts	This file is right at the limit; add a second attachment and it is exceeded.
Gmail	25 MB per message	Under the limit, although email encoding adds about a third in transit.
GitHub web uploads	25 MiB per file added through the browser	Accepted. Pushing with Git allows larger files.
Cloudflare Pages assets	25 MiB per file	The largest round size that can be served as a static asset.
Amazon API Gateway	10 MB payload	Rejected; the upload has to go directly to object storage.
ASP.NET Core (Kestrel)	About 28.6 MB request body by default	Accepted with room for the multipart overhead.

All 20 MB sample files

Use this file for

Testing email attachment limits
Baseline upload and download tests
Checking encoding handling

Testing notes for TXT

Plain text compresses very well, so a 10 MB text file may travel as a fraction of that when gzip or Brotli is enabled. Use the BIN samples when you need incompressible bytes.
Line endings change the byte count: converting LF to CRLF adds one byte per line, which breaks checksum comparisons.

TXT format reference

Technical details

File name	sample-txt-20mb.txt
Format	TXT (Plain text)
Extension	.txt
MIME type	text/plain
Size	20,971,520 bytes (20 MB)
Kind	Text
SHA-256	3913f245aa8fa5b964ef74e4b68876534b722b2336d296178eab652145217b69
Created	2026-10-14
Validation	Exact size, signature bytes and structure checked when the generator was built; your copy is checked against the SHA-256 after it is created
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	Documents

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

Verify your copy

This file is created in your browser, so it has no direct URL for curl or wget. The bytes are the same every time and in every browser, so after saving it you can compare its checksum with the SHA-256 value above.

sha256sum sample-txt-20mb.txt     # Linux
shasum -a 256 sample-txt-20mb.txt # macOS

On Windows, run Get-FileHash sample-txt-20mb.txt -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy, or use a 1 MB file, which has a direct URL.

Related files

Questions about this file

Is this file exactly 20 MB?: Yes. It is 20,971,520 bytes, which is 20 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 20 MB TXT file?: 210,979 numbered lines of plain English text, each prefixed with its line number and starting byte offset so truncation is easy to spot. A closing rule of "=" characters brings the file to the exact size.
Why does each line start with numbers?: Each line carries its line number and the byte offset where it begins. If a transfer is truncated or corrupted you can see exactly where.

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