Find inactive subscribers: split a list into active, cooling and sunset
In short: Reads the last open, last click or last activity dates in a Mailchimp, Klaviyo, Kit or other export, and sorts every subscriber into active, cooling off, inactive, never engaged, or new with no activity yet, with one CSV per group. Limit: It only knows the dates in your export; activity the platform didn't record or didn't export isn't counted.
To find inactive subscribers, export your list with its last open, last click or last activity dates, upload the CSV here and set your windows, such as active within 90 days and inactive after 180. Every subscriber is sorted into active, cooling off, inactive, never engaged or too new to judge, with a CSV for each group.
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
Between the two is 'cooling off'.
Empty means today. Use the export date for an older file.
Sample result
7 subscribers sorted: 2 active, 1 cooling off, 2 inactive, 1 never engaged, 1 too new to judge.
- Inactive
- 2 of 7
- Active
- 2
- Never engaged
- 1
What this means for you
Win back the cooling and inactive ones, and check those addresses before the send.
- Last open, click and activity dates
- Active, cooling, inactive, never
- New signups held apart
- One CSV per segment
- Sunset
- Engagement
- CSV
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I check inactive subscribers before a win-back?
- Download the cooling off, inactive and never engaged files here.
- Upload them at /verify. Every address gets a live mailbox check, and the ones whose mailbox has closed come back invalid. The first 100 email checks are free with a Google sign-in, no card.
- Send the win-back only to the valid addresses, and suppress the invalid ones in your platform.
How do I find inactive subscribers in an email list?
- Export your audience or profiles from your email platform with the engagement date columns (last open, last click, last activity) and the signup date.
- Set the active window and the inactive cut-off; leave the date empty to measure from today, or use the export date for an older file.
- Upload the CSV and press Find inactive subscribers. Date columns are found by their headers, and the latest date in any of them counts.
- Download each group: keep mailing the active ones, send a win-back to the cooling and inactive ones, and suppress whoever doesn't respond.
Example
- You enter
- A 7-subscriber export with Date Added, Last Open and Last Click columns, measured from 1 November 2026 with active within 90 days and inactive after 180.
- You get
- 2 active (last activity 4 and 12 days ago), 1 cooling off (153 days), 2 inactive (306 and 994 days), 1 never engaged since joining in 2021 and 1 who joined 20 days ago held apart as new. 4 go into the win-back file.
- Limits
- Runs in your browser with no row cap; an uploaded file can be up to 25 MB.
What counts as an inactive email subscriber?
Someone who hasn't opened or clicked for longer than your sending cycle makes sense of. For a weekly newsletter that is usually three to six months; for a store that emails a few times a year, longer. The windows are yours to set: anyone with activity inside the first is active, anyone with none for longer than the second is inactive, and the gap between is cooling off, the group a win-back is most likely to reach.
Subscribers with no activity date at all are never engaged, unless they signed up inside the active window, in which case they are too new to judge.
Are opens a reliable sign of activity?
Less than they were. Apple Mail Privacy Protection loads remote content privately for people who turn it on (Apple: Mail Privacy Protection), which records an open whether or not the person read the email. Clicks, purchases and logins are harder evidence.
So when your export has both, this tool uses the latest of all the activity dates it finds, and you can drop the open column from the file before uploading if you want clicks only.
Should I delete inactive subscribers?
Not straight away. Send them a short re-engagement series, then suppress whoever still doesn't respond, as our sunset policy guide and re-engagement campaign guide describe. Mailbox providers watch how recipients engage, and Google's sender guidelines tie inbox placement to it (Email sender guidelines).
Long-silent addresses are also where closed mailboxes collect, so the win-back itself can bounce. Checking those addresses first keeps the re-engagement send from hurting the reputation it is meant to protect.
Is this faster than a formula in Excel?
| This tool | Excel or Sheets | |
|---|---|---|
| Days since last activity | Computed | =TODAY()-MAX(D2:E2) |
| Mixed date formats | Read and normalised | Often stored as text |
| Groups as separate files | One step | Filter and save each |
| New signups held apart | Yes | Another formula |
Who uses this tool, and for what?
- Newsletter owners
- Find the readers who haven't opened in six months before the list's size pushes you into a higher plan.
- Ecommerce
- Split a Klaviyo or Shopify Email export into active buyers and a win-back group with their last activity dates.
- Agencies
- Show a client how much of their list is cooling off or inactive, with a file for each group.
- SaaS teams
- Pick out signups who never engaged before a product announcement goes to everyone.
What can’t this tool tell you?
- It only knows the dates in your export; activity the platform didn't record or didn't export isn't counted.
- Opens can be recorded by privacy features without anyone reading the email, so open-only activity overstates engagement.
- Date columns are found by header names; rename an unusual one, such as Last Engaged Date, if it isn't picked up.
- Inactive isn't the same as invalid: a silent subscriber's mailbox may still exist.
Common questions
- How do I find inactive subscribers in Mailchimp?
- Mailchimp's audience segments can filter on campaign activity; to work on the file instead, export contacts with their activity dates and upload the CSV here.
- How long before a subscriber is inactive?
- There's no fixed rule; 90 to 180 days of no opens or clicks is a common range for a list mailed weekly. Set it to match how often you send.
- What date formats does it read?
- 2026-10-20, 10/20/2026, 20/10/2026 (day first, detected or chosen), 20 Oct 2026, and Unix timestamps.
- Is my list uploaded?
- No. Dates are read in your browser and nothing is sent anywhere unless you choose to check addresses afterwards.
- How do I know which inactive addresses no longer exist?
- Upload the inactive file at /verify. Each address gets a live mailbox check without an email being sent, and the first 100 checks are free with a Google sign-in, no card.
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.