System · BAT
A 15 MB BAT file, on demand.
Exactly 15,728,640 bytes of a Windows batch script with a real @echo off header, built on your machine the moment you press the button.
15,728,640 bytes, exactly.
Every byte above the 111 bytes structural minimum goes into unreachable text after a goto :eof, which cmd.exe never parses, which is why this file still behaves like one a real user would send.
Unit convention
15 MB on this page means exactly 15,728,640 bytes, using the binary (MiB) convention some systems label "MB" for short. 1 MB in the strict decimal sense is 1,000,000 bytes; 1 MiB is 1,048,576 bytes — the readout above always shows the exact count either way.
Approximate size equivalents
Roughly 8,738 pages of typed text, 16 minutes of 128 kbps audio, 1 minute of CD-quality audio, 6.3 photos from a 12 MP camera. These figures compare file size only — the generated file does not contain this text, audio or image content.
Accepted by
Outlook.com attachment, Gmail attachment, Cloudflare Free proxy body — all publish a limit at or above this size, based on commonly cited figures that can vary by plan and change over time.
Rejected by
Discord free attachment, AWS API Gateway payload, PHP default upload_max_filesize — this exceeds their commonly cited limit, which makes it a useful negative test. Published limits can vary by plan and change over time.
Other BAT sizes
Mail servers and chat apps draw the line in this band — Gmail attachments stop at 25 MB, and plenty of APIs cap request bodies alongside them.
15 MB in other system formats
Questions.
Is this 15 MB BAT file valid?
Yes. It is a Windows batch script with a real @echo off header. The extra bytes sit in unreachable text after a goto :eof, which cmd.exe never parses, so it opens in Notepad, VS Code and cmd.exe.
Does 15 MB mean 15,728,640 bytes?
On this page, yes — 15 MB uses the binary (MiB) convention, so the file is exactly 15,728,640 bytes. 1 MB in the strict decimal sense would be a different, smaller byte count. Upload validators may use either convention, so the exact byte count is always shown to remove any ambiguity.
What is a 15 MB file used for?
Mail servers and chat apps draw the line in this band — Gmail attachments stop at 25 MB, and plenty of APIs cap request bodies alongside them. For BAT specifically, the usual job is testing script upload handling and text-file size limits.
Where is the file downloaded from?
Nowhere. It is assembled in a Web Worker on your own device and handed to the browser as a Blob, so nothing is uploaded, fetched or stored.