5 MB M4A sample file

An M4A file of exactly 5,242,880 bytes. It is a valid MPEG-4 audio file, generated for this site and checked with an independent parser. Use it wherever you need a 5 MB sample, test or dummy M4A file.

sample-m4a-5mb.m4a

5 MB5,242,880 bytes

Download 5 MB M4A

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

Type: audio/mp4
SHA-256: 446a17173eac8fb56ebc2e466a7266d0710ce182bcaebe6bec751756bf0ee93e
Delivery: Created in your browser. Files of 2 MB and more have no direct URL (why).

What is in this file

14,021 AAC frames (5 min 26 s) of a synthesised musical phrase that repeats every eight seconds, in one audio track. 224 bytes of a trailing "free" box bring the file to the exact size.

Duration	5 min 26 s
Audio codec	AAC-LC
Bit rate	128 kbit/s
Sample rate	44,100 Hz
Channels	Stereo
Container	MPEG-4 (brand "M4A ")
Fast start	Yes (moov before mdat)

First bytes of the file

The first 64 bytes of sample-m4a-5mb.m4a as a hex dump: offset, bytes, then the same bytes as text. The M4A signature is 66 74 79 70 4D 34 41 20 at offset 4.

00000000  00 00 00 1c 66 74 79 70 4d 34 41 20 00 00 02 00  |....ftypM4A ....|
00000010  4d 34 41 20 6d 70 34 32 69 73 6f 6d 00 00 e2 60  |M4A mp42isom...`|
00000020  6d 6f 6f 76 00 00 00 6c 6d 76 68 64 00 00 00 00  |moov...lmvhd....|
00000030  e5 7b 69 80 e5 7b 69 80 00 00 03 e8 00 04 f7 bf  |.{i..{i.........|

Preview

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

Where 5 MB matters

A 5,242,880-byte file: the size of a phone photo and the minimum part size for S3 multipart uploads. These are the default limits a file of this size is useful for testing:

System	Limit	Note
PHP	2 MB per uploaded file by default (upload_max_filesize)	A 5 MB upload fails on an untuned PHP installation.
Vercel Functions	4.5 MB request body	Larger uploads must go directly to object storage.
Amazon S3 multipart upload	5 MiB minimum part size	This file is exactly one minimum part.
AWS Lambda	6 MB synchronous invocation payload	5 MB of binary data exceeds it once base64-encoded.
Browser localStorage	About 5 MB per origin	Storing this file as text fills the quota.
Django	2.5 MB in memory by default	Larger uploads are streamed to a temporary file instead of held in memory.

All 5 MB sample files

Use this file for

Testing image resizing and memory use
Verifying type detection between audio and video MP4
Testing transcoding to MP3 or Opus

Testing notes for M4A

AAC encoders add a short run of priming samples before the real audio. Players that do not account for it report a slightly longer duration and leave a gap between tracks that should join seamlessly.
Three media types are in circulation: audio/mp4, audio/x-m4a and audio/m4a. Browsers send different ones for the same file.

M4A format reference

Technical details

File name	sample-m4a-5mb.m4a
Format	M4A (MPEG-4 audio)
Extension	.m4a
MIME type	audio/mp4
Size	5,242,880 bytes (5 MB)
Kind	Binary
Signature	66 74 79 70 4D 34 41 20 at offset 4
SHA-256	446a17173eac8fb56ebc2e466a7266d0710ce182bcaebe6bec751756bf0ee93e
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	Audio

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-m4a-5mb.m4a     # Linux
shasum -a 256 sample-m4a-5mb.m4a # macOS

On Windows, run Get-FileHash sample-m4a-5mb.m4a -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 5 MB?: Yes. It is 5,242,880 bytes, which is 5 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 5 MB M4A file?: 14,025 AAC frames (5 min 26 s) of a synthesised musical phrase that repeats every eight seconds, in one audio track. 322 bytes of a trailing "free" box bring the file to the exact size.
Which codec do the M4A samples use?: AAC-LC at 128 kbit/s, 44,100 Hz stereo, which is the combination every device and browser plays.

Download