Slack and Teams File Size Limits

Most teams discover these limits at the worst possible moment — mid-handoff, with someone waiting. The two platforms behave very differently, and in both cases the published number is only half the story. Here's what's actually going on.

The Limits Side by Side

	Slack	Microsoft Teams
Max per file	1 GB	Up to 250 GB (business)
Changes with plan?	No — same on all plans	Personal use far lower (~5 GB total)
Where files live	Slack storage	SharePoint / OneDrive
Counts against storage?	Yes	Yes
Free plan catch	90-day history window	Limited total storage

Slack: 1GB on Every Plan

Slack's per-file limit is 1GB, and the genuinely surprising part is that this doesn't change when you pay. Free, Pro, Business+ and Enterprise Grid all share the same ceiling. If you've been told that upgrading will let you share bigger files, that's wrong — upgrading buys you more storage and longer message history, not a higher per-file cap.

For most office work 1GB is plenty. Where it bites is creative and technical work: video exports, design files with embedded assets, datasets, raw photography. Those routinely exceed it.

There's a second limit that causes more confusion than the first. On the free plan, Slack only keeps the last 90 days of messages and files accessible, and once you reach the storage allowance older files get archived to make room. Archived files vanish from channels and from search. So a file you shared six months ago may simply not be there any more — which is a problem if your team treated Slack as the place where a document lives.

Teams: Big Limit, Hidden Cost

Teams looks far more generous, allowing single files up to 250GB on business plans. The reason for that enormous figure is that Teams isn't really storing your file at all — when you drop something into a chat or channel, it goes into SharePoint (for channels) or OneDrive (for direct chats). The Teams limit is just the SharePoint limit.

That architecture has a consequence worth understanding. Every file casually dropped into a Teams chat consumes your organisation's SharePoint or OneDrive allocation, and it stays there indefinitely. Nobody deletes files out of old chat threads. Over a couple of years, informal file sharing in Teams becomes a significant and completely invisible chunk of storage — and when your tenant runs low, tracking down the cause is genuinely painful.

Teams for personal use is a different product with much tighter limits, around 5GB of total storage. If you're using the free consumer version, don't plan around the 250GB figure.

The Real Blocker Is Usually External Sharing

Here's the thing that trips up more people than either size limit: getting a file to someone outside your organisation.

Both platforms are built around internal collaboration. Sharing with an external client, contractor or agency typically means one of:

• Adding them as a guest, which needs admin approval in many organisations
• Generating an external sharing link, which IT policy frequently restricts or disables outright
• Asking them to create an account on a platform they don't use

None of that is about file size. A 10MB contract can be just as hard to send externally as a 10GB video, and in strict environments the answer is simply no. Meanwhile the person waiting for the file doesn't care about your tenant's sharing policy.

This is the situation where a transfer link genuinely solves a problem that neither platform solves well. Your recipient needs nothing — no guest account, no app, no access to your workspace, no sign-up. Just a browser.

What to Do When You Hit a Wall

Internal, slightly over the limit. Compress it, or split a folder into logical parts. For Slack, consider whether it belongs in the team's actual document storage instead of a chat thread — chat is a poor filing system.

Internal, far over the limit. Use your organisation's proper storage — SharePoint, Drive, a network share — and post the link in chat. That's what these tools are for, and it keeps the file findable later.

External recipient. This is where a transfer tool earns its place:

1. Open realtimesender.com and drop in the file — up to 30GB, free, no account.
2. Copy the 6-character code or link.
3. Send it however you're already talking to them — email, Slack Connect, a text.
4. They download the original. The file then deletes itself automatically.

Being straight about the trade-off: because the file auto-deletes after download or when the code expires, this is for delivery, not for giving a client ongoing access to a shared folder. For a long-running collaboration, proper storage with real permissions is the right answer. For "here's the final export, due today," a transfer link is faster and leaves nothing behind.

One practical habit worth adopting either way: before sending anything sensitive outside the company, check what your organisation's policy actually permits. Our guide to secure file sharing for teams and businesses covers that side in more depth.

Frequently Asked Questions

What is the Slack file size limit?

1GB per file, and unusually, that figure is the same on every Slack plan. Free, Pro, Business+ and Enterprise Grid all share the same per-file ceiling, so upgrading your subscription does not let you upload bigger files. Paid plans give you more storage and longer history, not a higher per-file limit.

What is the Microsoft Teams file size limit?

Up to 250GB for a single file on business plans. That is because files shared in Teams are actually stored in SharePoint or OneDrive, so the Teams limit is really the SharePoint limit. Teams for personal use is far more restricted, with around 5GB of total storage.

Why can't I upload a file to Slack even though it is under 1GB?

Usually storage rather than file size. On the free plan older files are archived to make room once you reach the storage allowance, and archived files disappear from channels and search. A slow or interrupted connection on a large upload is the other common cause.

Do files shared in Teams count against our storage?

Yes. Because Teams files live in SharePoint or OneDrive behind the scenes, every file dropped into a chat or channel consumes your organisation's storage allocation and stays there until someone deletes it. Casual file sharing in chat is a common and invisible cause of storage growth.

What is the best way to send a large file to someone outside my company?

External sharing is often blocked or restricted by IT policy, which makes it a bigger obstacle than file size. A transfer link avoids the problem entirely because the recipient needs nothing but a browser, no guest account, and no access to your workspace.