Slack accepts files up to 1 GB each, on the Free plan and on every paid plan, and you can drag up to ten files into one message. A file over 1 GB is refused at upload rather than trimmed. On a free workspace the limit that bites more often is time: messages and files older than 90 days disappear from view and search.
Which limits apply?
| Limit | Value | Applies to |
|---|---|---|
| Size per file | 1 GB | every plan |
| Files per message | 10 (drag and drop) | every plan |
| Visibility of messages and files | last 90 days | Free plan |
| Apps and integrations | up to 10 | Free plan |
| Inline preview of Office files | none above 50 MB | every plan |
| Inline preview of images | none above 25,000 px on the longest side or 45 million px in total | every plan |
| Text snippets created through the API | 1 MB | every plan |
The figures come from Slack's own pages: Add files to Slack, Usage limits for free workspaces and the pricing page. Slack no longer publishes a storage pool per plan on those pages; older guides quote 5 GB for the whole free workspace and 10 to 20 GB per member on paid plans, so treat those numbers as historical.
What happens to files after 90 days on the Free plan?
Files and messages older than 90 days are hidden, not deleted. They stay in Slack's storage, return if the workspace moves to a paid plan, and the workspace owner can choose in the retention settings to keep everything for a year or delete after 90 days. If a client sent you a delivery through Slack three months ago and you can no longer find it, that is the reason.
How do you share a file larger than 1 GB?
Three options, from least to most control.
- Compress it. A
.zipshrinks documents, layered design files and project folders. It does almost nothing for photos and video, which are already compressed. - Post a link from cloud storage. Slack connects to Google Drive, Dropbox and Box through its app directory (up to ten apps on the Free plan). The file lives in the storage service and the message carries the link, so Slack's limit no longer applies. The recipient needs permission in that service.
- Send a transfer link. A transfer service uploads the files once and gives you a download link to paste in the channel or the direct message. Brault Transfer sends up to 2 GB per transfer on the free plan (5 transfers a month) and up to 250 GB per transfer on Growth, with a branded download page, an optional password and an expiry date. The plans and limits page lists every cap.
Email has the same problem at a smaller scale: see What is the Gmail attachment size limit? for the 25 MB case.
Why does the upload succeed but the preview is missing?
Slack shows the file as an attachment without an inline preview when a Microsoft Office file is over 50 MB or an image exceeds 25,000 pixels on its longest side or 45 million pixels in total. The upload is complete and the file downloads normally. For very large photos and design exports, a preview-friendly copy (a JPEG under those dimensions) next to the original saves the recipient a download.