Microsoft 365 Business vs Mailu
In short: Microsoft 365 Business wins on privacy, Microsoft 365 Business wins on price, and Microsoft 365 Business wins on features. The full comparison is below, last checked 25 October 2026.
Which should you choose?
- Microsoft 365 Business is the better pick if you want your mail kept in the UK data centres for UK tenants (London, Cardiff, Durham) and a calendar and contacts alongside your mail.
- Mailu suits you best if you want a provider with no advertising business behind it; a free plan before you pay anything; and open-source apps anyone can check.
| Feature | Microsoft 365 Business | Mailu |
|---|---|---|
| Overall | 2.5 | Not rated |
| Privacy | 1.0 | Not rated |
| Price | 2.5 | Not rated |
| Features | 5.0 | Not rated |
| Cheapest plan | Business Basic £5.40 per user a month, yearly, ex VAT | Open source Free |
| Free plan | No | Yes, open source |
| Storage | 50 GB | Not confirmed |
| Your own domain | ✓ Yes | ✓ Yes |
| End-to-end encryption | No | No |
| Company based in | United States | Not confirmed |
| Your data is kept in | UK data centres for UK tenants (London, Cardiff, Durham) | Your own server |
| Founded | 2011 | Unknown |
| Free trial | One month free on some plans | Free to download |
| Funded by advertising | Yes, or its parent company is | No |
| Works in any mail app | ✓ IMAP and SMTP | ✓ IMAP and SMTP |
| Calendar and contacts | ✓ Yes | No |
| Aliases | Yes | Yes |
| Open-source apps | No | ✓ Yes |
| Sign up without ID | No | No |
| White label | No | Unknown |
| Reader offer | None | None |
| Last checked | 22 October 2026 | 25 October 2026 |
Want to add another? Open this in the compare tool.
The key differences
- Microsoft 365 Business's cheapest plan is Business Basic (£5.40 per user a month, yearly, ex VAT); Mailu's is Open source (Free).
- For free, Microsoft 365 Business gives you no free plan, and Mailu a free plan (open source).
- Microsoft 365 Business comes with 50 GB of storage and Mailu with storage not confirmed.
- Microsoft 365 Business keeps your mail in the UK data centres for UK tenants (London, Cardiff, Durham), while Mailu keeps it in Your own server.
- Microsoft 365 Business is based in the United States and Mailu in Not confirmed, so different privacy laws apply.
- Only Microsoft 365 Business is part of an advertising business.
Microsoft 365 Business and Mailu: your questions
Do Microsoft 365 Business and Mailu work with my own domain?
Yes, both do. Microsoft 365 Business: Yes. Mailu: Yes.
Where do Microsoft 365 Business and Mailu keep my email?
Microsoft 365 Business keeps it in the UK data centres for UK tenants (London, Cardiff, Durham). Mailu keeps it in Your own server.
Recent price changes
- 27 July 2026 Microsoft 365 Business: £5.40 (UK price change from 1 July 2026)
- 1 June 2026 Microsoft 365 Business: £4.90
The latest headlines: Microsoft 365 Business news · Mailu news.
Not sold on either? Try these
- mailbox.org4.5 out of 5 overall
- Proton Mail for Business4.0 out of 5 overall
- Tuta Business4.0 out of 5 overall
Microsoft 365 Business vs mailbox.org · Mailu vs mailbox.org · Microsoft 365 Business vs Proton Mail for Business · Mailu vs Proton Mail for Business · Microsoft 365 Business vs Tuta Business · Mailu vs Tuta Business
Switching between them
Moving to Microsoft 365 Business · Moving from Microsoft 365 Business. Or see all my switching guides.