How do I use my own domain name for Microsoft 365 email?

The short answer: add your domain in the Microsoft 365 admin centre under Settings > Domains, prove you own it by adding a TXT record at whoever manages your domain's DNS, then add the email records Microsoft gives you. The step that needs care is changing the MX record, because that's the moment new email starts arriving in Microsoft 365 instead of wherever it goes today.

Why bother with your own domain?

When you first sign up, Microsoft 365 gives you an address ending in something like yourbusiness.onmicrosoft.com. It works, but it doesn't look like a real business. An address like you@yourbusiness.co.uk:

• looks professional and trustworthy to customers
• matches your website, so people recognise it
• stays yours if you ever change email provider

Before you start

You'll need two things:

• Admin access to Microsoft 365. You need to be a Global Administrator or have a domain admin role.
• Access to your domain's DNS. This is usually wherever you bought the domain (your registrar, such as 123 Reg, GoDaddy or Cloudflare), but sometimes your web designer manages it. If you're not sure, a free online "whois" or DNS lookup will show who hosts it.

Also check whether you already use the domain for email somewhere else. If you do, you'll need to plan moving that email across, which we cover below.

Step 1: Add and verify your domain

1. Sign in to the Microsoft 365 admin centre at admin.microsoft.com.
2. Go to Settings > Domains and click Add domain.
3. Type your domain name, for example yourbusiness.co.uk, and click Use this domain.
4. Microsoft will ask you to verify it. The usual method is adding a TXT record that starts MS=ms followed by a number.
5. Add that TXT record at your DNS host, wait a few minutes, then click Verify.

For some well-known DNS hosts, Microsoft can add the records for you automatically once you sign in to them. That's handy, but read what it's about to change before you agree.

Step 2: Add the email records

Once verified, the wizard shows the records you need. Use the exact values it gives you, as they're specific to your domain. The main ones are:

• MX record: tells the world where to deliver your email. This is the big switch.
• Autodiscover CNAME: points autodiscover to autodiscover.outlook.com, so Outlook can set itself up automatically.
• SPF TXT record: lists the servers allowed to send email for your domain. If Microsoft 365 is your only sender, it's usually v=spf1 include:spf.protection.outlook.com -all. If you also send from other systems, they need adding too. See SPF, DKIM and DMARC explained.

You may also see optional records for Teams and device management. Add them if you use those features.

Step 3: Plan the switch if you already have email

If the domain already has email elsewhere (another provider, or an old host bundled with your website), changing the MX record moves where new email arrives. Your old emails don't move by themselves.

A safe order is usually:

1. Create everyone's account in Microsoft 365 first. See how to add a user in Microsoft 365.
2. Copy existing email, contacts and calendars across using a migration tool, or Outlook if it's just one or two people.
3. Change the MX record, ideally at a quiet time like a Friday evening.
4. Run a final catch-up copy for anything that arrived at the old system during the switch.
5. Set up Outlook and phones with the new accounts.

Step 4: Switch on DKIM

Once email is flowing, turn on DKIM. It adds a digital signature to your email, which helps it land in inboxes rather than junk. It's switched on in Microsoft Defender and needs two more CNAME records at your DNS host.

Watch out for your website

Your domain's DNS also controls your website. When you edit records, only add or change what Microsoft asks for. Don't delete existing A or CNAME records for your website, and don't change your nameservers unless you know exactly where everything else will end up. Breaking your website while fixing your email is a classic Friday afternoon mistake.

Common questions

Can I use more than one domain?

Yes. You can add several domains to one Microsoft 365 account, and people can have addresses on more than one of them. Each domain needs verifying and its own email records.

How long does it take?

Adding and verifying a domain often takes under an hour. DNS changes usually work within minutes, but can occasionally take up to 48 hours to reach everywhere. Moving existing email takes longer, depending on how much there is.

Will I lose emails during the switch?

Not if it's done in the right order. Email keeps arriving at either the old or new system while the MX change spreads, which is why a final catch-up copy matters.

What happens to my onmicrosoft.com address?

It stays. It's a permanent part of your account and still receives email, but people won't see it once your own domain is set as the default.