Shared Mailbox vs Distribution List : Compare all Differences
Are you a new O365 admin struggling to prevent double replies to the same message? Maybe you want a sure-shot way to make new hires aware of the historical conversations? All this can be possible if you know how to choose between a Shared Mailbox vs Distribution List.
Don’t have much time? Here is a TL;DR
When you think of a shared mailbox, think of a centralised inbox (like a bucket). No login required, its members connect directly and can read or reply to the messages in real-time.
On the other hand, the distribution list is more like a microphone. It is a virtual address that routes the emails to multiple individuals’ personal inboxes.
Those of you who want to clear the confusion once and for all, go through this guide and become fully aware of the differences, use cases, features, and limitations.
Before anything else, let’s see where both coincide.
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Similarities Between A Shared Mailbox and a Distribution List
Yes, differences are there, but there are also some things in common. Both shared mailboxes and distribution lists have their own generic email address. And you can’t tell just by looking at the email address if it’s a shared mailbox or a distribution list.
Moreover, any message sent to that address is received by every member of that particular shared mailbox or distribution list at the same time.
You don’t require a separate password to access a shared mailbox or distribution list; it is part of your default mailbox.
As the email address has such a critical role in the functioning of these features, novice admins may confuse both of these features with standard email aliases. They should not be compared; Alias is a completely different ball game. You add aliases to one specific user, not the team. If that is what you are looking for, I suggest you go and create an email alias in Outlook instead of building a shared or distribution group.
Additionally, you might not know this, but Shared Mailboxes and Distribution lists aren’t the only collaborative features of O365. There are plenty of other Office 365 mailbox types that you would encounter while working in the M365 ecosystem. So use my detailed guides to stay on top of any future challenges.
The Core Differences: Storage vs. Routing
The most fundamental difference between a Microsoft 365 Distribution List vs Shared Mailbox comes down to the place where emails are kept.
When you create a Shared Mailbox in Office 365. A separate 50 GB of space gets assigned. This is not part of any user’s mail storage. Rather, a separate container that counts towards the entire organization’s pooled quota.
On the other hand, the distribution list has no separate storage space of its own. The emails that are sent via a distribution list auto-redirect or route the message to recipients’ accounts and are kept there. So in a way, it uses the storage of the participant’s mailbox.
When a member reads an email in a shared mailbox, it is automatically marked as “read” for every other member as well. Email replies, deletions, and modifications all get reflected to all in real-time. This prevents duplicate work.
Distribution lists have no shared history, as they are like a forwarding engine managed from the admin center. The emails enter individual mailboxes, so none of the other members know if you have read your copy of the message or not. What you do with the message stays within the bounds of your account.
Shared Mailbox vs Distribution List: Feature-by-Feature
This tabular graph will help you make an administrative decision. Use it to study how each option handles data, user access, and backend Microsoft 365 limits.
| Feature | Shared Mailbox | Distribution List |
| Main Purpose | Team collaboration on the same emails. | One-way broadcasting to a large group. |
| Email Destination | Stored in one central, shared inbox. | Forwarded to members’ personal inboxes. |
| “Read” Status | Synchronized. Read by one = read by all. | Independent. Does not affect others. |
| Storage Weight | Has its own server storage (Inbox, Sent, etc.). | Uses zero storage space. |
| Historical Access | Yes. New members see all past emails. | No. New members only see future emails. |
| Shared Calendar | Yes. Full shared calendar and contacts. | No. You must share a calendar in Office 365 separately. |
Shared Mailbox vs Distribution List Use Case Comparison
Shared Mailboxes works best for scenarios like: Customer Support (support@), Sales Inquiries (sales@), Billing Departments (invoices@), and reception desks where collaboration and replies are the norm.
You should use a Distribution List whenever the task is: Company-wide announcements (all-employees@), department newsletters, emergency alerts, or automated system endpoints where you expect less/no action and just want to broadcast information.
After learning all this, you might have the urge to try the features on your own. For that, I have a practical guide that demonstrates how to create your own Shared Mailbox and Distribution List.
Difference Between Distribution List and Shared Mailbox Creation Process
Building a Shared Mailbox vs a Distribution list in M365 requires an entirely different set of permissions. So, before you make them, make sure you have an Office 365 admin account. Make a new Office 365 admin account if need be.
Then follow my guide on How to create a Shared Mailbox in Office 365 or How to create a Distribution List in Outlook 365, depending on your needs.
Can I Convert a Shared Mailbox to a Distribution List and Vice Versa?
Making a distribution list into a Shared mailbox is super easy. In fact, the admin center has dedicated buttons for such conversion scenarios.
The opposite is not true; the nature of Shared Mailboxes puts them closer to a regular user mailbox, and thus making it into a storage-less distribution list goes against the M365 guidelines.
You could theoretically do it, but not without losing tons of important message data along the way. In my experience, it’s simply not worth it.
Nevertheless, as your organization scales and grows, there will be times when you, as an admin, will be put in charge of managing the technical parts of the M&A, so it doesn’t hurt to be prepared with the right guide on how to manage multiple Office 365 tenants.
Conclusion
Here, I taught you everything there is to know about Shared Mailbox vs Distribution List, theory-wise. What I want you to take from this is explained with this equation:
Collaboration = Shared Mailbox. Broadcasting = Distribution List.
However, real lessons only become apparent when you use these features practically on your own. So I suggest getting hands-on with the Shared Mailbox and Distribution list to develop an intuitive understanding of how these collaborative features operate and when it’s better to use one over the other.
Last but not least, being an admin means that often in your career you will find yourself in positions where you need to consolidate O365 tenants or conduct a full-on Office 365 tenant-to-tenant migration. In such scenarios, the SysTools Office 365 to Office 365 migration tool is the best choice.
Get your free demo today.
Frequently Asked Questions
Q: Do I need a license for an Office 365 Shared Mailbox vs. a Distribution list?
You don’t need to buy separate licenses for either of those. However, if your Shared mailbox storage exceeds 50 GB or requires advanced archiving features, you need to assign a license to it.
Q: Can I send an email from the Outlook Distribution list and the Shared Mailbox?
It is possible to send emails via a Shared Mailbox, but you can only send emails to a distribution list. In fact, recipients do not even receive any notification or message that they are part of a distribution list; for them, it’s like receiving an email from the sender directly.
Q: Do I need a password to access a Shared mailbox or a Distribution list?
The only password you need is your account login password; there are no separate login credentials for accessing the Shared Mailbox or Distribution list.
Q: Is it possible to add external participants to a shared mailbox or distribution list?
Yes for Distribution List, no for Shared Mailbox. Distribution lists, being a simple forwarding mechanism, have less scrutiny on their membership, so even people outside your organization can be part of it. However, shared mailboxes are more sensitive in that regard, and only people who have the correct internal tenant credentials get to see their contents. External users are either outright forbidden or only have read-only access.
Q: How many people can be a part of a Shared mailbox compared to a Distribution list?
The difference is massive; on one hand, Distribution lists are designed to support up to 100,000 members. Shared mailboxes are designed for smaller teams, with Microsoft recommending no more than 25 concurrent users at a time.