How to Split Email Addresses into Username and Domain Columns
To split an email address, everything before the last @ is the username and everything after it is the domain: jane+news@mail.acme.co.uk splits into jane+news and mail.acme.co.uk. The email address splitter adds those columns to every row of a pasted list or CSV, plus the username without its +tag, the subdomain, the registrable domain (acme.co.uk) and the ending (co.uk).
Formulas stop at username and domain; the registrable domain is where a split at the last dot goes wrong.
The by-hand way
- Excel 365:
=TEXTBEFORE(A2,"@",-1)for the username and=TEXTAFTER(A2,"@",-1)for the domain. The -1 splits at the last @. - Older Excel:
=LEFT(A2,FIND("@",A2)-1)and=MID(A2,FIND("@",A2)+1,255), or Data > Text to Columns with @ as the delimiter. - Google Sheets:
=SPLIT(A2,"@")fills both columns.
For counting addresses per domain once you have them, see how many emails are on each domain.
Step 1: load the list
Paste addresses or upload a CSV export. The email column is found automatically and every column is kept.
Step 2: choose the tag separator
- for most providers, - for some self-hosted servers, or none. Only one separator is applied per run. For why tags matter, see stripping +tags from a list.
Step 3: split and download
Press Split the addresses and download the CSV with seven new columns, or copy just the usernames or the domains. The registrable domain uses the ICANN section of the Public Suffix List, so eu.acme.com and acme.com group together, which helps when limiting contacts per company.
What this check cannot do
- It splits text; it does not check that the address or domain works.
- Private suffixes such as github.io are not split off, because only the ICANN section is used.
For a domain-only column, the email to domain extractor is the shorter route.
Next: check which of these mailboxes exist
Splitting leaves the addresses unchecked. Run them through the verify page: the first 100 email checks are free with a Google sign-in, no card. Each comes back valid, risky or invalid with a reason, and nothing is sent to anyone on the list. For larger lists, see bulk email verification, list cleaning and pricing.
Try it now
Open the email address splitter.
Common questions
How do I split an email at the @?
Everything before the last @ is the username and everything after it is the domain. In Excel 365, TEXTBEFORE and TEXTAFTER with -1 do this; in Google Sheets, SPLIT(A2,"@").
Why split at the last @?
A rare quoted address can contain an @ in the username, so splitting at the last one is the safe choice.
What is the registrable domain?
The company's domain without mail or regional subdomains, such as acme.co.uk from mail.acme.co.uk.
Which columns does the tool add?
Seven new columns: the username, the username without its +tag, the domain, the subdomain, the registrable domain and the ending, among them.
Does it check that the address works?
No. It splits text only.
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.