20 MB MP3 sample

An MP3 file of exactly 20,971,520 bytes. It is a valid MPEG-1 Audio Layer III file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 20 MB sample, test or dummy MP3 file.

sample-mp3-20mb.mp3

20 MB20,971,520 bytes

Download 20 MB MP3

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

Type: audio/mpeg
SHA-256: 05180d99aab48602a3792df6f4613da87ab17e21fe690263a787061a9af49237
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

50,175 MPEG audio frames (21 min 51 s) of a synthesised musical phrase that repeats every eight seconds, after an ID3v2.3 tag. 386 bytes of zeros in the tag's standard padding area bring the file to the exact size.

Duration	21 min 51 s
Bit rate	128 kbit/s constant
Sample rate	44,100 Hz
Channels	Stereo
Format	MPEG-1 Audio Layer III
Tags	ID3v2.3 (title, artist, album, genre)

First bytes of the file

The first 64 bytes of sample-mp3-20mb.mp3 as a hex dump: offset, bytes, then the same bytes as text. The MP3 signature is 49 44 33.

00000000  49 44 33 03 00 00 00 00  03 6a 54 49 54 32 00 00 |ID3......jTIT2..|
00000010  00 13 00 00 00 53 61 6d  70 6c 65 20 4d 50 33 20 |.....Sample MP3 |
00000020  28 32 30 20 4d 42 29 54  50 45 31 00 00 00 10 00 |(20 MB)TPE1.....|
00000030  00 00 53 61 6d 70 6c 65  54 65 73 74 46 69 6c 65 |..SampleTestFile|

Preview

Creates the file in your browser and shows it here. Nothing large is downloaded from our server.

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

Measuring download speed from your own server or CDN
Testing transcoding and podcast pipelines
Testing audio upload and playback

Testing notes for MP3

A large ID3 tag with artwork can push the first audio frame far into the file, confusing naive sniffers.
Duration is not stored in a header. Players estimate it from bit rate and file size, which goes wrong for variable-bit-rate files that lack a Xing header.

MP3 format reference

Technical details

File name	sample-mp3-20mb.mp3
Format	MP3 (MPEG-1 Audio Layer III)
Extension	.mp3
MIME type	audio/mpeg
Size	20,971,520 bytes (20 MB)
Kind	Binary
Signature	49 44 33
SHA-256	05180d99aab48602a3792df6f4613da87ab17e21fe690263a787061a9af49237
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	Audio

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-mp3-20mb.mp3     # Linux
shasum -a 256 sample-mp3-20mb.mp3 # macOS

On Windows, run Get-FileHash sample-mp3-20mb.mp3 -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 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 MP3 file?: 50,175 MPEG audio frames (21 min 51 s) of a synthesised musical phrase that repeats every eight seconds, after an ID3v2.3 tag. 386 bytes of zeros in the tag's standard padding area bring the file to the exact size.
What is on the MP3 samples?: A short synthesised musical phrase that repeats. It was generated by code for this site, so it is free of any music copyright.

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