To track sent emails that nobody has answered, you need something that looks at the thread after you sent, not at your inbox. Gmail does it with nudges, Outlook only with a flag you set yourself, and neither covers a second account. Below is what each one does, the follow up schedule we use, and where the gaps are.
The three ways to track an unanswered email
Gmail nudges are automatic but not configurable, Outlook flags are manual but exact, and a cross-account list is the only one that covers every mailbox. The table puts the three side by side. The Gmail and Outlook rows come from the pages we opened on October 23, 2026, the Nolario row from how its waiting-for-a-reply list is built.
| Feature | Nolario | Gmail | Outlook |
|---|---|---|---|
| Who starts it | Automatic, for mail you sent | Automatic nudge, on by default | You, before you send |
| When it comes back | After 3, 5 and 8 days | About 2 to 5 days, not settable | At the date and time you set |
| What you get | The thread plus a follow-up draft | A suggestion to follow up | A reminder dialog and a task |
| Several accounts | Gmail, Outlook and IMAP together | Per Gmail account | Per Outlook account |
| Stops by itself | After the third follow-up | Not stated | Not stated |
Nolario: a list of who owes you a reply
The most reliable tracker is one that reads the thread for you and tells you who owes a reply. Nolario is our product, so weigh this pick accordingly. We list it first because it checks whether the last human message in a thread is yours, for Gmail, Outlook and IMAP mailboxes, and brings the thread back in Smart Priority after 3, 5 and 8 days (counted from your last mail) with a follow-up already drafted in your voice.
Three rules keep it quiet. An out-of-office reply does not count as an answer. A mail to more than six people is treated as a broadcast, not a conversation. After the third unanswered follow-up it stops, because nagging a dead thread is noise. Whether a mail expects an answer at all, a plain "thanks" does not, is decided by a model, not by a keyword list.
The limits are plain. It looks back 30 days, it never sends, you open the draft in the Drafts tab and press send yourself, and it does not track opens or read receipts. It is a desktop web app and access is by waitlist. See the integrations and pricing pages.
Gmail: turn nudges on and use them
Gmail nudges are on by default and resurface sent mail that went quiet, with a prompt such as "Sent 5 days ago. Follow up?" 9to5Google reported both examples when Google launched them on May 14, 2018. Mailmeteor, on April 23, 2026, puts the usual delay at 2 to 5 days and says you cannot change it.
- Click the gear icon and choose See all settings.
- On the General tab, scroll to the Nudges section.
- Check "Suggest emails to follow up on" for sent mail, and "Suggest emails to reply to" for mail you have not answered.
- Scroll to the bottom and click Save Changes.
The same article lists when nudges do not appear: mail sent to a large group or mailing list, threads you starred, snoozed or archived, messages filtered out of your main inbox, and messages Gmail does not flag as high priority. A quiet thread to a client can sit in that last group.
Outlook: flag the message before you send it
Outlook tracks an unanswered mail only if you flag it yourself, and Microsoft's page does not say that Outlook alerts you when no reply arrives. On the Message tab choose Follow Up, pick a timeframe such as Today, Tomorrow, This Week or Next Week, and add a reminder with Follow Up, then Add Reminder and a date and time.
Microsoft's page adds that the message will be out of sight in your Sent Items folder, so it recommends adding a reminder for yourself. A flag for yourself also adds a to-do item. You can also flag for recipients, with a reminder on their side, but Microsoft advises using that with discretion because it interrupts them. The page applies to Outlook for Microsoft 365 and the 2016 to 2024 desktop versions.
A follow-up schedule that does not nag
Follow up three times at most: 3 days after your mail, 5 days after the first follow-up and 8 days after the second, then stop. Each message should be shorter than the last and make it easy to answer.
- First follow-up, 3 days after your mail: one line that restates the question and the date you need an answer by.
- Second, 5 days after the first: offer a smaller ask, such as a yes or no, or two time slots.
- Third, 8 days after the second: say you will assume the answer is no, or hand the decision back.
- After that, stop and move the thread to a call or another channel.
The schedule is the one built into Nolario's waiting list. It applies equally by hand in Gmail and Outlook. For writing the message itself, see how to write faster email replies with AI. For the incoming side of the same problem, see how to triage 200 messages a day and what to delegate when you answer your own email.
