How to Tell a Business Email From a Personal One (and Is This Domain Free?)
An email is personal if its domain is a consumer mailbox provider that anyone can sign up to: gmail.com, outlook.com, yahoo.com and their regional and ISP cousins. It is business if the domain belongs to an organisation, like jane@acme.com. The quick test is a lookup against a list of free provider domains. The edge cases (old aliases, ISP addresses, companies hosted on Google or Microsoft) are where most filters go wrong.
The 30-second test for any domain
Ask three questions in order, and stop at the first yes.
- Is the domain on a free-provider list? gmail.com, googlemail.com, outlook.com, hotmail.com, live.com, msn.com, yahoo.com, ymail.com, icloud.com, aol.com, proton.me, gmx.com, and regional ones such as yahoo.co.uk or web.de. If yes, it's personal. Our free email providers list covers 79 of them, checked for live MX records, with a CSV download.
- Is it a disposable domain? Addresses meant to be thrown away, from services like Mailinator or 10 Minute Mail. If yes, it's neither personal nor business. It's junk. Check any domain against our disposable domain directory, which tracks 8,740 of them.
- Does the domain have a business website? Visit the domain. A company site means a business address. If the site offers anyone a free mailbox, it's a provider you've found that the list missed.
The edge cases that break simple filters
Aliases of the big providers
Free providers own more domains than people remember. These are all personal, and all routinely missed by filters that only check gmail.com, yahoo.com and hotmail.com:
| Domain | Belongs to | MX on 11 Oct 2026 |
|---|---|---|
| googlemail.com | Gmail | gmail-smtp-in.l.google.com |
| live.com, msn.com | Outlook.com | *.olc.protection.outlook.com |
| ymail.com, rocketmail.com | Yahoo Mail | mta5.am0.yahoodns.net |
| me.com, mac.com | iCloud Mail | Apple |
We cover the Google one in googlemail.com vs gmail.com, and the Microsoft ones in Hotmail, Outlook, Live and MSN.
ISP addresses
comcast.net, att.net, verizon.net, sbcglobal.net, cox.net, btinternet.com, sky.com: these come with an internet connection, so they're personal. Several aren't even run by the ISP anymore. When we checked in October 2026, att.net, sbcglobal.net, verizon.net, cox.net, rogers.com and sky.com all had MX records pointing at Yahoo.
Companies on Google Workspace or Microsoft 365
Here the MX records are misleading. jane@acme.com might have MX records pointing at aspmx.l.google.com or acme-com.mail.protection.outlook.com. That only says Acme pays Google or Microsoft to run its mail. The address is still business.
So never classify by MX host alone. Classify by the domain, and use the MX host only to learn how mail is handled. Our domain lookup shows both for any domain.
Free providers with paid tiers
Proton, Zoho and Fastmail sell business plans on custom domains, but they also give out personal addresses on their own domains (proton.me, zohomail.com, fastmail.com). The rule holds: their own domain is personal, a custom domain is business.
Small businesses on Gmail
A plumber at smithplumbing@gmail.com is a real business using a personal domain. That's why blocking all free addresses on a B2B form costs you customers. Most teams accept them and either ask for a company name or score them lower.
What to do with the split
- Signup forms: flag rather than block, and block disposable domains outright. See blocking disposable emails at signup.
- Lead lists for B2B outreach: keep business addresses in the main sequence, and send personal ones a different, lighter one, or drop them. Your reply data will tell you which.
- Deliverability: personal addresses at Gmail, Outlook and Yahoo are where the bulk sender rules apply hardest, so verify them before you send.
Checking a whole list
The domain test tells you who an address belongs to. It doesn't tell you whether the mailbox exists. Both matter: a business address that bounces is worse than a personal one that's delivered.
Drop your CSV into the free list check to see, with no signup, how many rows are duplicates, typos, disposable or on dead domains, plus a live mailbox check on a sample. The paid plan then checks every mailbox and lets you export valid, risky and invalid addresses separately.
Common questions
How do I know if an email domain is a free email provider?
Check it against a list of consumer mailbox domains such as gmail.com, outlook.com, yahoo.com and their regional and ISP variants. If the domain is on the list, the address is personal. If it isn't, look at the domain's website: a company domain has a business behind it, a free provider offers signups to anyone.
Is an email on Google Workspace or Microsoft 365 a business email?
Usually yes. The MX records will point at Google or Microsoft, but the domain itself belongs to the company. Hosting tells you who runs the mail servers, not who owns the address, so judge by the domain, not the MX host.
Are ISP addresses like comcast.net or att.net business emails?
No. They are personal addresses issued to internet customers. Some, like att.net and verizon.net, are even received by Yahoo's mail servers. Treat them as personal.
Should I block personal email addresses on a B2B signup form?
Usually not outright. Freelancers, founders and small-business owners often use Gmail. A softer approach is to accept them and ask for a company name, or score them lower, rather than turning away real buyers.
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