Find duplicate emails in Excel or Google Sheets, flagged in place
In short: Flags repeats instead of deleting them: each row gets Unique, First of N or Duplicate of row N (another sheet's row when you compare a whole workbook), ignoring capital letters and optionally Gmail dots and +tags, as a column you paste back. Also the COUNTIF formula. Limit: It reads one column per sheet: the one with the most addresses. A second email column on the same sheet isn't compared.
To find duplicate emails in Excel or Google Sheets, paste the email column here or upload the .xlsx. Every row gets a flag: Unique, First of 3, or Duplicate of row 12, ignoring capital letters. Paste the flag column back next to your data and filter it. Uploading a workbook can also find the same address on two sheets.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Sample result
[email protected] is on rows 2 and 4: row 4 is flagged Duplicate of row 2.
- Row 4
- [email protected]
- First copy
- Row 2
- Copies
- 2
What this means for you
Flags sit beside your data, so you can merge details before you delete a row.
- Paste a column or upload an .xlsx
- Unique, First of N, Duplicate of row N
- Across sheets and Gmail dots
- COUNTIF formula included
- Excel
- Google Sheets
- Duplicates
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Duplicates found. Now check the addresses that are left.
- Download the deduplicated list, one row per address.
- Upload or paste it at /verify. The first 100 email checks are free with a Google sign-in, no card.
- For every list after that, Pro includes unlimited email verification. Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.
How do I find duplicate email addresses in Excel?
- Copy the email column in Excel or Google Sheets from row 1 (header included), or upload the .xlsx to check every sheet.
- Choose whether gmail.com addresses that differ only by dots or a +tag count as the same, and whether to compare across sheets.
- Press Find duplicates. Each row is flagged with where the address first appears.
- Copy the flag column and paste it into an empty column on row 1, or download the deduplicated list.
Example
- You enter
- A pasted Email and Name column:
[email protected],[email protected],[email protected], a blank row,[email protected],[email protected],[email protected]. - You get
- Flags in row order: Duplicate check (header), First of 2, First of 2, Duplicate of row 2, blank, Unique, Duplicate of row 3, Unique. With the Gmail option on,
[email protected]becomes Duplicate of row 6 and[email protected]First of 2. - Limits
- Runs in your browser; an uploaded file can be up to 25 MB, every sheet of an .xlsx is read.
How do I highlight duplicate emails in Excel?
Select the column, then Home > Conditional Formatting > Highlight Cells Rules > Duplicate Values. It colours every copy, the first one too, so you can't tell which to keep. To mark only the second and later copies, add a helper column with =IF(COUNTIF($A$2:A2,A2)>1,"Duplicate","") and fill it down; COUNTIF counts how many times the address has appeared so far.
In Google Sheets the same formula works, and Format > Conditional formatting > Custom formula =COUNTIF($A:$A,$A2)>1 highlights every repeated row.
Why flag duplicates instead of removing them?
Because the rows often differ. Two rows for one address can carry a different name, owner or stage, and Excel's Remove Duplicates keeps the first and silently drops the rest. A flag column shows each repeat and the row it repeats, so you can merge the details before deleting anything.
When you only need the clean list, the remove duplicate emails tool drops the repeats and keeps your other columns.
Are emails with different capital letters duplicates?
Yes. Mail servers treat the domain as case-insensitive and almost all of them treat the name the same way, so [email protected] and [email protected] reach one inbox; the tool compares lowercased addresses. Excel's COUNTIF is case-insensitive too.
Gmail goes further: it ignores dots in the name and anything after a +, so [email protected] is [email protected] (Google). Tick the Gmail option to count those as repeats. Company domains on Google Workspace don't ignore dots, so the option only touches gmail.com and googlemail.com.
This tool, conditional formatting or COUNTIF?
| This tool | Conditional formatting | COUNTIF helper column | |
|---|---|---|---|
| Says which row it repeats | Yes, Duplicate of row 12 | No | No |
| First copy left unmarked | Yes, First of N | No, all copies coloured | Yes |
| Across sheets | Yes, with a workbook upload | No | Needs a formula per sheet |
| Gmail dots and +tags | Optional | No | No |
| Name <email> cells | Address read from inside | Whole cell compared | Whole cell compared |
Who uses this tool, and for what?
- Sales ops
- Flag the leads two reps both added to the shared sheet, with the row of the first copy, before assigning them.
- Event teams
- Upload the registrations workbook and find attendees who signed up on two ticket sheets.
- Cold emailers
- Merge three list sources in one workbook and see which addresses appear on more than one before you pay to verify them twice.
What can’t this tool tell you?
- It reads one column per sheet: the one with the most addresses. A second email column on the same sheet isn't compared.
- Only the first address in a cell is used; split cells with several addresses first.
- Old .xls files aren't read. Save as .xlsx, or copy the column and paste it.
Common questions
- How do I find duplicate emails in two columns in Excel?
- Paste both columns' addresses into one column here, or upload a workbook with each list on its own sheet and tick Compare across sheets. Each repeat says which sheet and row it first appears on.
- How do I find duplicates in Google Sheets?
- Copy the column and paste it here, or add =COUNTIF($A:$A,A2)>1 as a custom conditional formatting rule to highlight every repeated row.
- Does Remove Duplicates in Excel ignore case?
- Yes. Excel's Remove Duplicates treats [email protected] and [email protected] as the same and keeps the first row.
- Is my spreadsheet uploaded?
- No. The file and the pasted cells are read in your browser.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.