Is a Calendar Invite From Someone You Don't Know a Scam?

Short answer: treat it as a scam. Don't tap Accept, Decline or any link inside it. Delete it, report it, and change one setting so strangers can't put events in your calendar again.

How the calendar invite scam works

A meeting request arrives from someone you don't know. Because email and calendars work together, the event often appears in your calendar on its own, even if you never opened the email. Some even stay on your calendar after the email itself has been caught by a spam filter.

The invite is dressed up to look urgent or official. Common disguises include an invoice query, a payment or refund, a missed voicemail, a subscription renewal, a security warning about your account, or a normal-looking work meeting. Inside is a link, a phone number, a QR code, or an attached file.

1. Fake sign-in pages. The link leads to a page that looks like Microsoft, Google, or your bank, and steals your password when you type it in.
2. Harmful downloads. Some links download a program that lets criminals control your computer remotely.
3. Phone scams. Some invites list a "support" number to call, where a fake agent asks for your card details or a code.

Why it's suddenly everywhere

Security researchers at Check Point counted a few thousand malicious calendar invites a month in April 2026. By September it was more than 118,000 a month, and in just the first two weeks of October, more than 740,000. Scammers like calendar invites because they land in two places at once, and people tend to trust anything that appears in their own schedule.

Warning signs

1. You don't know the sender, or it comes from a free email address pretending to be a company.
2. It's about money: an invoice, payment, refund, or charge.
3. It asks you to sign in, download a file, scan a QR code, or call a number.
4. It's urgent: "your account will be closed", "payment overdue", "action required today".
5. It's a reminder of something you don't remember, designed to make you click to check.

What to do with a strange invite

1. Don't respond. Don't tap Accept, Maybe, or Decline.
2. Don't click anything inside it, including links, files, and QR codes, and don't call any number it gives.
3. Delete the event from your calendar, and delete the email.
4. Report the email as spam or phishing in your email app. If it came to a work account, tell your IT team.
5. If it seems to come from someone you know, contact them another way before you click. Their account may have been hacked.

Stop strangers adding events to your calendar

Google Calendar: open Settings, go to Event settings, find "Add invitations to my calendar", and choose "Only if the sender is known". Invitations from people you've never dealt with will still reach your email, but they won't appear in your calendar unless you accept them. The change applies to new invitations, so delete any strange events already there.

Outlook: open Settings, go to Calendar, then Events and invitations, and turn off adding events to your calendar from email, or limit it to known senders. The exact wording varies between Outlook versions. Spam invites can sometimes still appear, so keep your junk filter switched on and delete anything suspicious without responding.

If you already clicked or signed in

1. Change your password straight away on the real website or app, not through the invite, and change it anywhere else you used the same one.
2. Turn on two-step verification and sign out of all other devices.
3. If you downloaded a file, disconnect from the internet and run a full security scan. On a work device, tell your IT team immediately.
4. If you gave card or bank details, call your bank on the number on the back of your card.

The rule is simple: your calendar is not proof that something is real. If you didn't plan it and you don't know the sender, delete it without responding.

Sources: Help Net Security: The explosion of invite-based attacks (Check Point and Sublime Security research) · Google Calendar Help: Manage invitations in Calendar · Which?: The latest scam alerts