How to Tell if an Email Address Is Gmail, Outlook or a Company Mailbox
Look at the domain after the @, then at that domain's MX records. A free webmail domain such as gmail.com, outlook.com or hotmail.com means a personal mailbox. Anything else is a company domain, and its MX records name the company that hosts its mail. The email provider lookup reads the MX and SPF records and tells you: Google Workspace, Microsoft 365, Zoho, another provider, or a security gateway in front of one.
Check the provider with the lookup
- Open the email provider lookup.
- Enter an email address, a domain (
acme.com) or a website URL. - Press Find the provider. The tool queries the domain's MX and SPF records.
- Read the headline: the mailbox provider, a gateway in front of it, a forwarding service, or no mail at all.
- Check the MX table for the raw hosts and the SPF line for the services allowed to send as the domain.
Check by hand
dig +short MX acme.com
On 8 November 2026 these domains returned:
| Domain | MX host | Means |
|---|---|---|
| gmail.com | gmail-smtp-in.l.google.com | Personal Gmail |
| microsoft.com | microsoft-com.mail.protection.outlook.com | Microsoft 365 (company) |
| outlook.com | outlook-com.olc.protection.outlook.com | Personal Outlook.com |
A company domain with MX hosts ending in google.com is on Google Workspace; one ending in mail.protection.outlook.com is on Microsoft 365. On Windows use nslookup -type=mx acme.com.
Free webmail, or company mailbox?
The domain decides it. gmail.com, googlemail.com, outlook.com, hotmail.com, live.com, yahoo.com, icloud.com and similar are consumer services. Our free email providers list and Hotmail, Outlook, Live and MSN domains list the common ones. A personal Gmail and a Google Workspace mailbox both run on Google, but only the domain tells you whether it's a person or a company account.
When the MX shows a gateway
Many companies filter inbound mail through Proofpoint, Mimecast, Barracuda or similar first, so the MX names the gateway. The SPF record usually shows the real provider: include:spf.protection.outlook.com for Microsoft 365, include:_spf.google.com for Google Workspace. That's strong evidence, not proof. Gateways also make mailbox checks harder; see verifying emails behind security gateways.
A whole list?
Use the bulk email provider lookup: upload a CSV of up to 5,000 rows and 1,000 unique domains, and each row is labelled by provider. Segmenting a list by mailbox provider covers what to do with the split.
Next step: check the mailbox, not only the provider
The provider tells you who runs the mail, not whether this address exists. Upload your list at /verify: each address gets a live mailbox check without sending, and each row also shows its provider. The first 100 checks are free with a Google sign-in, no card.
Pro, $39 a month: Unlimited email verification.* Never metered, never cut off. See pricing.
*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.
Common questions
How can I tell if an email is a Gmail account or Google Workspace?
An address ending in @gmail.com or @googlemail.com is a personal Gmail account. An address on a company domain whose MX records point to Google is Google Workspace.
How do I know if a company uses Outlook / Microsoft 365?
Look up the domain's MX records. Microsoft 365 mail servers end in mail.protection.outlook.com. The email provider lookup names it for you.
Does the lookup email the address?
No. It reads two DNS records, MX and TXT, for the domain. Nothing is sent to the mail server.
Can I check a whole list of addresses?
Yes. Use the bulk email provider lookup: upload up to 5,000 rows and 1,000 unique domains, and each row is labelled Google, Microsoft, Yahoo, Zoho, Proton, other, or no mail server.
Check your list before you send
Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.