Flagging marks an email so you notice it later
Flagging is a feature in most email programs that puts a visible marker on a message — usually a colored flag, star, or exclamation point — so the email stands out in your inbox. When you flag an email, nothing happens to the message itself. It stays in your inbox in the same place. The flag is just a visual signal that tells you this one matters and you should come back to it.
Different email programs show flags differently. Gmail calls it a star and displays a yellow outline around the message. Outlook uses a colored flag icon next to the sender's name. Apple Mail shows a flag in the message list. Regardless of how your program displays it, the purpose is the same: to separate messages you need to act on from the ones you can ignore for now.
Flagging is not the same as marking an email as important or moving it to a folder. The email stays exactly where it is. You are straightforward adding a marker that makes it easier to spot when you are scanning your inbox quickly or looking for something specific later.
Key Takeaways
- Flagging adds a visible marker to an email without moving it or changing its content, making it stand out in your inbox.
- Use flags for emails that need a response, contain information you will need soon, or require you to take action by a certain date.
- Most email programs let you search for or filter flagged messages, so you can pull up all your flagged emails at once.
- Flagging works best when you use it consistently for the same types of messages — mixing purposes defeats the point.
- Flags are a temporary tool; once you have acted on a flagged email, you should remove the flag to keep your system clean.
When to flag an email instead of other options
Flag an email when you need to respond to it but cannot do so right now. If your boss sends you a message asking for a report by Friday and it is only Monday, flag it. When you glance at your inbox later in the week, the flag reminds you the message exists and the important date is coming. Without the flag, the email gets buried under newer messages and you might forget.
Flag emails that contain information you will need to reference later but do not warrant their own folder. A confirmation number for a package delivery, a recipe someone sent you, or the details of a meeting time all fit here. The flag tells you "this one has something I might look up" without forcing you to sort it into a category.
Do not flag every email. If you flag too many messages, the flag loses its meaning — your inbox becomes a sea of flags and none of them stand out. Reserve flags for messages that genuinely need your attention or action within the next few days.
How to flag an email in common programs
In Gmail, click the star outline next to the subject line. The star fills in with yellow and the email moves to a "Starred" label on the left side of the screen. Click the star again to remove the flag. You can also search for starred emails by typing "is:starred" in the search box.
In Outlook, right-click the email and select "Flag" from the menu, or click the flag icon next to the sender's name. A menu appears asking when you want to be reminded about the message — you can choose "Today", "Tomorrow", "This Week", or "Next Week". Outlook will then remind you at that time. To remove the flag, click the flag icon again and select "Clear Flag".
In Apple Mail, click and hold on the flag column next to the message, or right-click the email and select a flag color from the menu. Different colors can mean different things if you want to organize that way — for example, red for urgent, orange for waiting on someone else. Click the flag again to remove it.
In Yahoo Mail and AOL Mail, click the flag icon next to the subject line. The flag fills in and the email is marked. Click it again to remove the flag. These programs do not offer color options or reminder timing the way Outlook does.
Using flags to find emails you flagged before
Most email programs let you view all your flagged messages in one place. In Gmail, click the "Starred" label on the left sidebar to see every message you have flagged. In Outlook, click "Flagged" in the left panel under "Search Folders". In Apple Mail, click the flag icon in the toolbar to filter the view to flagged messages only.
You can also search for flagged emails by typing a search term. In Gmail, type "is:starred" followed by a word or sender name. In Outlook, type "flag:true" in the search box. This is useful when you remember roughly what a flagged email was about but cannot locate it in your inbox.
If you flag a lot of emails, consider using colors or categories to separate them by type. Outlook's colored flags work well for this — you might use red for time-sensitive items, blue for messages waiting on someone else's response, and green for reference material. This way, when you view all your flagged emails, you can tell at a glance which ones need when ready action.
Why flagging works better than leaving emails unread
Some people try to keep track of messages that need action by leaving them marked as unread. This creates problems. Your unread count climbs, and after a while you stop trusting it — you might have 47 unread emails but only 3 actually need your attention. Flagging separates the messages that matter from the ones you have straightforward not gotten around to reading yet.
Flagging also works when you have already read an email but still need to act on it. If you read a message, reply to part of it, but realize you need to do something else before sending a full response, flag it. Leaving it unread would be misleading because you have already seen the content.
Another advantage: flagging is reversible and temporary. Once you have acted on a flagged email, you remove the flag and move on. This keeps your inbox from becoming a permanent graveyard of old flags that no longer mean anything.
Flagging versus folders and labels
Flagging is not a replacement for folders or labels — it serves a different purpose. A folder or label is permanent storage for related messages. You might have a folder called "Receipts" or "Work Projects" where you keep emails long-term. A flag is temporary. It says "deal with this soon" not "keep this forever in this category".
Use flags for the next few days. Use folders or labels for messages you want to find months from now. If an email needs both — for example, a work project update that you need to respond to this week and also keep for reference — flag it now and move it to a folder after you have acted on it.
Some people combine the two. They flag an email to remind themselves to respond, then after responding they move it to a project folder for long-term storage. This keeps your inbox clean and your flagged list focused on current action items.
Frequently Asked Questions
Does flagging an email notify the sender?
No. Flagging is something only you can see. The person who sent the email has no way of knowing you flagged it. It is purely a tool for organizing your own inbox.
Can I flag an email on my phone?
Yes, most email apps on phones and tablets support flagging. In Gmail's mobile app, tap the star icon. In Outlook mobile, tap and hold the email, then select "Flag". The flag syncs across all your devices, so if you flag an email on your phone, it will be flagged when you check email on your computer.
What if I flag too many emails and lose track?
Go through your flagged list once a week and remove flags from emails you have already acted on. If an email has been flagged for more than a week and you still have not done anything about it, either do it now or remove the flag. A flagged list that grows indefinitely becomes useless.
Can I set a reminder when I flag an email?
Outlook lets you set a reminder time when you flag — you can choose to be reminded today, tomorrow, this week, or next week. Gmail and Apple Mail do not have built-in reminder timing, but you can use your calendar or a separate task app to remind yourself about flagged emails if you need that feature.
Should I use different colored flags for different types of emails?
Only if you will actually use the color system consistently. If you flag 20 emails a day, color coding might help you spot urgent ones at a glance. If you flag one or two emails a week, a single flag color is simpler and works just as well. Keep it straightforward enough that you will stick with it.