When you request your Mastodon data archive, you receive a compressed file containing your posts, media uploads, follower lists, and account settings. The size of this archive can range from a few megabytes to several gigabytes depending on how long you have used the instance and how much media you have shared. Understanding what influences the final file size helps you plan storage space and estimate download time. This article explains the typical size ranges for Mastodon data archives, the factors that affect them, and what each component inside the archive contributes to the total.
Key Takeaways: Mastodon Data Archive Size Factors
- Preferences > Import and export > Request your archive: Triggers the server to generate a ZIP file containing your account data and media.
- Media attachments (images, videos, GIFs): Typically account for 80–95% of the total archive size, far more than text posts or metadata.
- Instance media retention policy: Some instances delete or downsample media after a set period, which reduces archive size.
What the Mastodon Data Archive Contains and Why Size Varies
The Mastodon data archive is a ZIP file generated by your instance server. It includes several folders and JSON files that represent your account activity on that instance. The main components are:
Text and Metadata Files
The archive contains JSON files for your account information, followers, following, lists, blocks, mutes, domain blocks, bookmarks, and preferences. These files are plain text and occupy very little space. For an account with 10,000 followers, the followers JSON file might be around 500 KB. The statuses JSON file lists every toot you have posted, including its content, timestamp, and reply context. Even with thousands of text-only posts, this file rarely exceeds 5 MB.
Media Attachments
The media_attachments folder contains every image, video, GIF, and audio file you have uploaded to your posts. This folder determines the overall archive size. A single high-resolution photo can be 3–5 MB. Videos are larger: a 30-second clip might be 10–15 MB. If you post media frequently, the archive can grow quickly. An active user with two years of daily posts containing images could expect an archive of 2–5 GB. A user who posts only text or links will see an archive under 50 MB.
Instance Media Retention Policy
Each Mastodon instance sets its own media retention rules. Some instances delete or downsample media after 30, 60, or 90 days. Others keep all media indefinitely. If your instance deletes old media, your archive will exclude those files, reducing the total size. Check your instance's terms or ask the admin to confirm the retention policy. This policy directly affects what you can expect when you request a data archive.
How Size Estimates Break Down by User Type
The following estimates assume the instance keeps all media for the entire account lifetime. Actual sizes vary based on posting frequency and media resolution.
Light User (Text-Only, Occasional Links)
A user who posts text-only statuses or shares links without embedded media will have an archive under 20 MB. The statuses JSON file and account metadata account for most of the size. Media attachments folder is empty or contains only a few small profile images.
Moderate User (Images in Most Posts)
A user who posts one or two images per day over six months will see an archive between 500 MB and 1.5 GB. Images are typically 1–3 MB each. The media_attachments folder dominates the archive size.
Heavy User (Videos, GIFs, Frequent Posts)
A user who posts multiple times daily with videos and animated GIFs over one year can expect an archive exceeding 5 GB. Videos from a smartphone can be 20–50 MB each. An archive of 10 GB or more is possible for very active accounts on instances with no media deletion.
Factors That Influence Archive File Size
Several variables affect the final ZIP file size beyond your personal posting habits.
Compression Ratio
The server compresses the archive using ZIP. Text files compress well, often shrinking to 10–20% of their original size. Media files, especially JPEG images and MP4 videos, are already compressed and do not shrink much further. The overall compression ratio for a media-heavy archive is low, typically 5–15% reduction. For a text-heavy archive, the ZIP file might be 30–50% smaller than the sum of the original files.
Number of Followers and Following
The followers.json and following.json files list account IDs and display names. Each entry is about 100–200 bytes. An account with 20,000 followers creates a JSON file of roughly 2–4 MB. This is small compared to media but adds up for very large accounts.
Account Age and Deleted Posts
The archive includes only statuses that still exist on the server. If you delete old posts, they do not appear in the archive. An older account with many deleted posts may produce a smaller archive than a newer account that has never cleaned up. The server does not store deleted content, so the archive reflects only current visible data.
Common Misconceptions About Archive Size
“The Archive Contains All My Data From Every Instance”
The data archive includes only the data stored on the instance where you request it. If you have moved accounts or used multiple instances, each instance holds separate data. You must request an archive from each instance individually. The archive does not include data from instances you have left.
“The Archive Includes Media From Other Users”
The archive contains only media you uploaded. It does not include media from other users' posts that you boosted or replied to. The archive is limited to your own account activity.
“The Archive Is the Same Size as Your Local Storage”
The archive is a compressed ZIP file, so its size is smaller than the sum of the original files on the server. When you extract the archive, the media_attachments folder may be 10–20% larger than the ZIP file itself. Plan for extracted storage that is roughly 1.2 times the ZIP file size.
Mastodon Data Archive Size Comparison: Light vs Heavy User
| Item | Light User (Text-Only, 6 Months) | Heavy User (Media Daily, 1 Year) |
|---|---|---|
| Number of statuses | 500 | 5,000 |
| Media attachments folder size | 5 MB | 4.5 GB |
| JSON metadata total size | 2 MB | 15 MB |
| Compressed ZIP file size | 6 MB | 3.8 GB |
| Estimated download time (50 Mbps) | 1 second | 10 minutes |
You can now estimate the size of your Mastodon data archive based on your posting habits and instance retention policies. To see your actual archive size, go to Preferences > Import and export > Request your archive and wait for the server to generate the file. For media-heavy accounts, consider requesting the archive during off-peak hours to avoid slow downloads. An advanced tip: if you only need the JSON metadata without media, some instances allow you to download the archive and then delete the media_attachments folder to save local storage space.