Restow vs Microsoft 365 Backup
Microsoft 365 Backup is Microsoft's own pay-as-you-go backup, billed at $0.15 per GB of protected content per month through the Microsoft 365 admin center. The backups stay inside Microsoft's infrastructure.
The short answer
Microsoft 365 Backup fits small tenants with little data, and anyone who wants backup without running anything: at 25 mailboxes with 10 GB each, it is cheaper than self-hosting Restow.
Restow fits when data grows or when you want a copy outside Microsoft: the per-GB bill rises with every gigabyte, while Restow costs a one-time license plus your own storage.
At a glance
| Aspect | Restow | Microsoft 365 Backup |
|---|---|---|
| Price model | Community free. Business €595, Service Provider €1,950, one-time, net (pre-sale until release: €476 and €1,560). No per-user fee. | $0.15 per GB of protected content per month, pay as you go, including deleted and versioned content held for recovery. |
| Where it runs | Self-hosted: one Docker Compose stack on a Linux server or VM you control. | Built into Microsoft 365; nothing to operate. |
| Where backups are stored | Your choice: local disk, S3-compatible object storage, NFS or SMB, in the region you pick. | Microsoft's own infrastructure. No other storage possible. |
| Microsoft 365 coverage | Exchange Online mail, calendar, contacts; OneDrive; IMAP mailboxes; Linux and macOS servers and clients (file-level agent); imported mail files. No SharePoint or Teams in version 1. | Exchange, OneDrive and SharePoint. |
| Restore testing | Weekly sampled restore: data is read back through the restore path and compared byte for byte. | Not researched for this comparison. |
| Source code and exit | AGPL-3.0 core, source-available Business and Service Provider modules, open documented storage format with a standalone restore tool. | Proprietary Microsoft service. |
Where Microsoft 365 Backup is strong
- Nothing to install or run; it is part of the admin center.
- A transparent, published price with no extra Azure charges.
- Deleted content stops being billed once it leaves the recovery window.
- At small data volumes, cheaper than any self-hosted setup.
Where Restow is different
- A copy outside Microsoft's infrastructure, which matters when the tenant itself is the problem (compromised admin, misconfiguration, account loss).
- A cost that does not grow per GB: Business €595 once, plus storage you choose.
- IMAP mailboxes too, not only Microsoft 365.
- A weekly restore test that reads data back and compares it.
5-year cost at three sizes
Restow at list price from release, plus server, storage and admin time, against Microsoft 365 Backup at its published list price. Net, in euros.
25 mailboxes
Microsoft 365 Backup is €4,136 cheaper
150 mailboxes
Restow is €745 cheaper
MSP, 20 tenants, 1,000 mailboxes
Restow is €44,037 cheaper
Microsoft 365 Backup keeps the data inside Microsoft; Restow keeps a copy outside. Every assumption and source · calculator with your numbers
When the per-GB price overtakes a one-time license
1 TB of protected content costs $150 per month, $1,800 per year, for as long as you keep it. Our 5-year cost chart runs three scenarios with every assumption listed: at 25 mailboxes Microsoft 365 Backup is cheaper, at 150 mailboxes and above Restow usually is, because its costs do not scale with gigabytes.
What Restow does not do (yet)
- Restow does not back up SharePoint or Teams in version 1.
- The audit log, SSO and roles are in development for Business.
- Licenses include no support; setup is available on quote.
- The server and endpoint agent runs on Linux and macOS, file-level; Windows is planned.
- Restow 0.1.0 is a beta: do not use it as your only backup.
Microsoft 365 Backup: the facts, with sources
Each line is taken from Microsoft 365 Backup's own documentation unless the rating says otherwise. "Checked: not found" means we looked in the named sources and did not find it, which is not proof that it does not exist.
| Fact | Source | How solid |
|---|---|---|
| Pay-as-you-go, consumption-based pricing. List price: $0.15 per GB per month of protected content. | Pricing model for Microsoft 365 Backup | Official source |
| Protected storage is the sum of: the live size of OneDrive accounts and SharePoint sites (including the first-stage recycle bin), the live size of protected mailboxes plus their online archives, and deleted/versioned content held for recovery (second-stage recycle bin, deleted or versioned mailbox items). | Same page | Official source |
| Restore-point frequency does not materially affect cost, and there are no additional Azure API or storage charges beyond the per-GB backup usage fee, even though Azure is used as the payment processor. | Same page | Official source |
| Deleted or versioned content stops counting toward the bill once it ages out of the backup's recovery window (e.g. 365 days after it was captured). | Same page | Official source |
| If a partner/ISV product is built on top of the Microsoft 365 Backup Storage platform, the customer is billed only by that partner, not separately by Microsoft. (Acronis's per-GB Microsoft 365 option, covered on its own comparison page, uses exactly this underlying platform.) | Same page | Official source |
| Storage is Microsoft's own infrastructure by definition. This is Microsoft backing up Microsoft's own service. There is no third-party or customer-controlled storage option, and none is offered. | Consistent with the product's own description; not a separate citation | Official source |
| Not open source: a native, proprietary Microsoft 365 admin-center feature. | Absence checked directly | Checked: not found |
| Export format and restore-verification specifics were not researched for this comparison. The scope of this research pass was the pricing model, and this page does not claim an answer either way on those points. | Not researched this pass | Open question |
Frequently asked
What does Microsoft 365 Backup cost?
$0.15 per GB of protected content per month, pay as you go. Protected content includes live data, online archives and deleted or versioned content held for recovery. Checked on Microsoft Learn on 2026-09-29.
Is Microsoft 365 Backup enough on its own?
It keeps backups inside Microsoft's own infrastructure. Many security guidelines recommend at least one copy outside the system being protected. Restow writes to storage you choose.
Is Restow cheaper than Microsoft 365 Backup?
Not for small tenants with little data: at 25 mailboxes Microsoft is cheaper over five years in our model. With more mailboxes and data, the one-time license usually wins. The assumptions are listed next to the chart.