Email re-verification due finder: which leads need checking again?
In short: Upload a list that has a column with the date each address was last verified, and set your own limit in days. Rows older than the limit, with no date or with a date that can't be read are pulled into a file to verify again; the recent ones are left alone. Limit: It trusts the dates in your file; a wrong date gives a wrong answer.
Upload a list with a column holding the date each address was last verified, and set how many days you let a check last. The tool reads the dates, measures each to today and gives you a file of the rows that are older than your limit, have no date or have a date it can't read, so you verify only those again and not the whole list.
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. Check your list free nowSee pricing
Your own rule, not a fixed one.
Sample result
Four of five rows are due: three are older than 30 days and one has no date.
- Verify again
- 4 rows
- Limit
- 30 days
- No date
- 1
What this means for you
Only those rows need another check, so you don't pay to verify the address checked 12 days ago.
- Reads common date styles
- Your limit in days
- No date counts as due
- Whole list with ages
- Re-verify
- Dates
- CSV
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Verify the due rows, and nothing else.
- Use the check button under the result to send the addresses that are due.
- Upload or paste it at /verify. Every address gets a live mailbox check, and the first 100 email checks are free with a Google sign-in, no card.
How do I find the emails to re-verify?
- Upload the list (.xlsx or CSV) or paste the cells, with an Email column and a column with the last-verified date.
- Set your limit in days, and say whether a date like 03/04/2026 is month first or day first.
- Check the date column the tool found, or pick another, and read the counts of rows older, undated and recent.
- Download the rows to verify again, check them, then write the new date into your file.
Example
- You enter
- Five addresses with a Verified on column: one verified 12 days ago, one 140 days ago, one 45 days ago, one with no date and one 300 days ago; limit 30 days.
- You get
- Four rows are due: the three older than 30 days and the one with no date. The address verified 12 days ago is left out. The file adds Days since verified and a Verification label to each row.
- Limits
- Runs in your browser; nothing is uploaded. Files up to 25 MB.
Which dates can it read?
It reads 2026-11-03, 11/03/2026, 3.11.2026, Nov 3, 2026, 3 November 2026 and Excel's serial numbers. A date such as 03/04/2026 fits both month-first and day-first, so it is read the way you choose; dates like 15/03/2026 can only be one thing and are read correctly either way. A cell it can't read counts as due, so a bad date never hides an address.
How long does a check stay good?
There is no fixed answer, which is why the limit is yours to set. A mailbox can close at any time, and people change employers: the U.S. Bureau of Labor Statistics publishes employee tenure data, which is one reason an old check says less over time. Mail servers also report some failures only after accepting a message (RFC 5321). Use the list decay calculator to model it, and how often to verify for the practice.
What does it do with rows that have no date?
They are counted as due. If you have never verified an address, there is nothing to say it still works, so it goes in the file of rows to check. A date in the future is not treated as due; it is counted separately so you can find the typo.
Who uses this tool, and for what?
- Cold emailers
- Re-check only the leads that sat in a sheet for months before a new campaign.
- Sales ops
- Keep a CRM export's verified dates honest by pulling the ones past your limit.
- Agencies
- Show a client which part of their list is stale and which is current.
What can’t this tool tell you?
- It trusts the dates in your file; a wrong date gives a wrong answer.
- It can't see whether a mailbox still works; only verification can.
- Dates in other languages or styles, such as next Friday, are not read.
- Two-digit years are read as 20xx.
Common questions
- Does this verify the emails?
- No. It only finds which rows are due, from the dates in your file. Verification is the next step, at /verify.
- What limit should I choose?
- Your own. Pick the number of days after which you stop trusting a check for your kind of list and your platform's bounce line.
- My file has no date column. Can I still use it?
- Yes. Choose None for the date column and every row is counted as due, which gives you the full list to verify.
- How is today decided?
- From your device's clock when you open the page, so the ages are right for the day you use it.
- Is my list uploaded to SimpleVerifier?
- No. The file is 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.