Old email list checker: is it safe to email a list you haven't mailed in months?
In short: From the list's age, source, engagement tiers and your platform: a verdict, the share likely gone stale against the platform's bounce line, consent windows, and a day-by-day restart by tier. Limit: The stale share is a model of job changes for work addresses; it isn't your list's measured rate.
Emailing an old list is safe only in stages. Enter how long since you last mailed and verified it, where the contacts came from and which platform you send with. You get a verdict, the share likely gone stale against your platform's bounce line, any consent windows that ran out, and a day-by-day restart from your most engaged contacts outward.
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
Leave blank if it never was.
Work-address decay modelled from BLS median job tenure.
Clicked, replied or bought. Opens are a weak signal.
The ramp stops growing here.
Old: 1 to 2 years since the last send
Verify, then ask the oldest contacts to confirm before mailing them
- Likely gone stale
- 1,795
- Share of the list
- 18.0%
- Brevo bounce line
- 2%
- Restart takes
- 8 days
- Verify all 10,000 first: 14 months since the last send, and it was never verified. About 18.0% likely gone stale is 9.0 times Brevo's 2% line.
- Widen only when the previous day's hard bounces stayed near zero and Gmail's spam rate stayed under 0.1%; otherwise hold the volume.
| Tier | Contacts | Send | Days |
|---|---|---|---|
| C: Whole list (no engagement data entered) | 10,000 | Re-permission email | Days 1–8 |
Starts at 250 a day and multiplies by 2 after each day, up to 2,000. These are your numbers: mailbox providers publish no safe ramp, only "start low with engaged users". Days assume one send a day with no pauses.
Next step
About 1,795 contacts have probably gone stale. A verification run finds which ones.
The estimate can't name the dead addresses. A mailbox check marks each address valid, invalid or risky before the restart, so the first days carry no hard bounces.
No list right now? This tool stays free, no account, so bookmark it for next time. Ctrl+D (⌘+D on a Mac)
Ready to verify now? Verify the list
Sample result
A list last mailed 14 months ago: verify it, then ask the oldest contacts to confirm before mailing them.
- Verdict
- Verify, then re-permission
- Likely stale
- 1,795
- Restart takes
- 9 days
What this means for you
About 18% likely gone stale is 9 times Brevo's 2% line, so it can't go out unverified.
- Stale share by age
- Against your platform's line
- CASL consent windows
- Day-by-day restart by tier
- Old list
- Re-permission
- Restart
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
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How do I check whether an old email list is safe to send to?
- Enter the list size, the months since it was last mailed and since it was last verified (leave verified blank if it never was).
- Pick where the contacts came from, the audience closest to yours for the decay model, and the platform you'll send with.
- If your platform shows engagement, enter how many people opened, clicked or bought in the last 6 months and 6 to 18 months ago.
- Set the first-day volume and how fast to grow it, then read the verdict and the restart plan.
Example
- You enter
- 10,000 opted-in contacts, last mailed 14 months ago, never verified, all-workers rate (15.6% a year), sending from Brevo, 2,000 engaged in the last 6 months and 3,000 in the 6 to 18 before, 250 on day 1 doubling up to 2,000 a day.
- You get
- Old: 1 to 2 years since the last send. Verdict: verify, then ask the oldest contacts to confirm. About 1,795 contacts (18.0%) likely gone stale, 9.0 times Brevo's 2% line. Tier A campaign on days 1 to 4, Tier B on days 5 to 6, Tier C a re-permission email on days 7 to 9.
- Limits
- Runs in your browser.
Is it safe to email an old email list?
Not all at once. Three things change while a list sits unused: people leave jobs and mailboxes close (hard bounces), some abandoned addresses come back as recycled spam traps, and people forget they signed up (complaints). Verification catches the first, and only partly the second; staging the restart by engagement handles the third. Our guide to mailing an old email list walks through the five stages this checker follows.
The stale estimate uses the same model as the email list decay calculator: the yearly share of people leaving their employer, from BLS median job tenure, compounded over the months since the list was last verified. It's a model for work addresses, not a measurement; for consumer lists there's no reliable published rate, so pick "No model" and verify a sample instead.
How many bounces will an old list cause?
More than most platforms allow. Eight months at the all-workers rate is about 10.7% stale, and Brevo's published bounce line is 2%, HubSpot's 5% and Instantly's default auto-pause 5% (bounce rate thresholds by platform). The checker divides the expected stale share by your platform's first published line, so you can see how far over an unverified send would go. Not every stale address bounces at once, so treat it as a size, not a forecast.
How should I restart sending to an old list?
Engaged contacts first, at a fraction of your old volume. Google's sender guidelines say to "start with a low sending volume to engaged users, and slowly increase the volume over time". The plan sends Tier A (engaged in the last 6 months) first, then Tier B (6 to 18 months), then Tier C, growing each day by the factor you choose up to your old daily volume. For lists over a year old, Tier C gets a re-permission email instead of a campaign. Every number in the schedule comes from your inputs; widen only when the previous day's bounces and complaints stayed low.
Permission comes before all of it. A bought or scraped list is a different question; the purchased email list checker covers the rules. In Canada, CASL's implied consent lasts two years from a purchase and six months from an inquiry (CASL and cold email).
Who uses this tool, and for what?
- Newsletter owners
- Restart a newsletter that went quiet for a year without one big send to everyone at once.
- Businesses after a migration
- Plan the first sends from a new platform to a customer list that came over from an old system.
- Agencies
- Show a client, with their own numbers, why their dormant list gets verified and staged before any campaign.
What can’t this tool tell you?
- The stale share is a model of job changes for work addresses; it isn't your list's measured rate.
- It can't see which contacts are stale, only roughly how many. Verification gives the real number.
- It isn't legal advice; consent rules depend on where your contacts are and how they joined.
- The restart volumes are the ones you choose; mailbox providers publish no safe ramp.
Common questions
- How old is too old for an email list?
- There's no single cut-off. Contacts not mailed for more than a year, or not engaged in 18 months, carry the most risk; they're the ones this checker sends a re-permission email rather than a campaign.
- Should I verify an old list before emailing it?
- Yes, every address that hasn't been verified or mailed successfully in the last three months. It removes the mailboxes that now bounce, which is the first damage an old list does.
- Can I email a list I haven't used in two years?
- Only after checking you still have permission, verifying it, and restarting with the most engaged contacts at low volume. Send the oldest segment a re-permission email and keep only the people who confirm.
- Does verification remove spam traps from an old list?
- Only some. A dead address is caught while it still bounces; once an operator turns it into a working trap it accepts mail like any other. That's why the oldest segment gets a re-permission email.
- How fast can I increase volume after a long break?
- Google publishes no number, only to start low with engaged users and increase slowly. The plan lets you set the first day and the daily growth, and you should hold or slow down whenever bounces or complaints rise.
Sources
Every address left in your cleaned list still need a mailbox check.
This tool removed what can be found without contacting a mail server. Whether each remaining mailbox actually exists can only be answered by asking the server that hosts it — an SMTP check — and that is what the paid plan 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
- Valid, risky and invalid exported as separate files
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.