Name: how-to-create-a-torrent-using-mktorrent

Last reviewed by: Clipper, April 2026

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Creating a torrent using mktorrent

mktorrent is a command-line tool for creating .torrent files. It is pre-installed on your Bytesized Appbox.

Basic usage

mktorrent -v -p -a http://tracker.url/announce -o filename.torrent folder_name

Important: The command must be all on one line. Use quotes around the folder name if it contains spaces.

Options

• -v — verbose output
• -p — set the private flag (disables DHT and PeerExchange, required by most private trackers)
• -a <url> — announce URL of the tracker. Use multiple -a flags to add backup trackers
• -o <filename> — output .torrent filename
• -l <n> — piece length as a power of 2 (see table below)
• -s <source> — source string embedded in the infohash (required by some trackers for cross-seeding)
• -n <name> — torrent name (defaults to the folder/file name)
• -c <comment> — add a comment to the torrent metadata
• -t <n> — number of threads for hash calculation (defaults to number of CPU cores)
• -d — omit the creation date from the torrent (useful for reproducible torrents)
• -w <url> — add a web seed URL

Example

To create a torrent for a release located at ~/torrents/completed/Artist - Album 2024:

cd ~/torrents/completed
mktorrent -v -p -a https://tracker.example.com/announce -o Artist-Album-2024.torrent "Artist - Album 2024"

To add a source tag and a backup tracker:

mktorrent -v -p \
  -a https://tracker.example.com/announce \
  -a https://backup.example.com/announce \
  -s tracker.example.com \
  -o Artist-Album-2024.torrent \
  "Artist - Album 2024"

Piece size guide

The -l flag sets the piece length as 2^n bytes. Use this table as a guide:

-l value	Piece size	Recommended for
19	512 KiB	512 MiB – 1 GiB
20	1 MiB	1 GiB – 2 GiB
21	2 MiB	2 GiB – 4 GiB
22	4 MiB	4 GiB – 8 GiB
23	8 MiB	8 GiB – 16 GiB
24	16 MiB	16 GiB – 512 GiB
25	32 MiB	Not recommended (incompatible with older clients)

If -l is not specified, mktorrent defaults to 18 (256 KiB), which is suitable for small files.