How to get your events onto customers' calendars

The short answer

You have four ways in: calendar invitations, an “Add to calendar” button, a calendar people subscribe to, and a connection to each customer's Google or Microsoft calendar. Invitations and buttons deal with one event at a time. Once a customer subscribes or connects, your new events reach their calendar with nothing more for them to do. A connected calendar takes your changes within moments, and a subscribed one picks them up at the app's next refresh, which can take hours.

What are the options?

	Calendar invitation	“Add to calendar” button	Subscription link	Connected calendar
What the customer does	Gets an email for each event, and accepts it if their calendar asks	Taps the button for each event	Subscribes once	Signs in with Google or Microsoft once
What you need from them	Their email address	Nothing	Nothing	Their permission to add events to their calendar
Your next event	You send another invitation	They come back and tap again	Appears at the app's next refresh	Added for them
When you change an event	Guests get the update, by email or in their Google Calendar	Their copy stays as it was	Shows after the next refresh	Changed in their calendar within moments
Works with	Anyone with an email address	Almost any calendar app	Apple Calendar, Google Calendar, Outlook and most others	Google and Microsoft calendars, plus the phones that show them

Our guide to “Add to calendar” buttons and calendar subscriptions compares those two in detail and covers which one suits which kind of event.

Can you send customers calendar invitations?

You can invite them from your own calendar. Google Calendar lets you add anyone with an email address as a guest, even someone who doesn't use Google Calendar, and guests get an email invitation. Put a crowd of customers on one invitation and you have a guest list to keep private, which our guide on sending an invite without showing everyone's email covers.

Whether the event lands on the calendar of someone who has never dealt with you depends on their settings. A Google Calendar user who picks “Only if the sender is known” gets events added automatically only from senders Google counts as known, such as people in their contacts, and an invitation email from everyone else. Our guide to Google's “known senders” setting explains it. An invitation the customer doesn't recognize can also look like spam, and we wrote about how people spot spam calendar events on iPhone.

What does an “Add to calendar” button do?

It gives the customer a copy of one event, which their calendar app saves when they tap. Microsoft says importing a calendar file gives you “a snapshot of the events in the calendar at the time of import,” so a copy made before you moved the event keeps the old time. A button works in nearly every calendar app, and it suits a one-off event that won't move.

Can customers subscribe to your calendar?

They can. You publish a calendar link and people add it to their calendar app once. Their app then downloads your calendar again from time to time, so new events and changes appear on their side without anyone sending anything. AddEvent, which hosts subscription calendars, puts Google Calendar's checks at every 12 to 24 hours. Microsoft's estimate is “approximately every 3 hours” in Outlook.com and every 6 hours in Outlook on the web with a work or school account, and some changes take more than 24 hours. Our guide on why a subscribed calendar isn't updating goes through the other apps. In Apple's words, “You can’t edit calendars you are subscribed to.”

A public link is the same for everyone who uses it. A free public Google Calendar is one way to publish it, and our guide on using a public Google Calendar for your business looks at when that's enough. Google's help page says subscribing has to happen in a web browser on a computer, so Android users have their own steps, which we cover in how to subscribe to a calendar on Android.

How does a connected calendar work?

The customer signs in with their Google or Microsoft account and grants permission to add and change events in their calendar. From then on your events get created in their calendar through Google's or Microsoft's calendar service, and when you move or cancel one, their copy changes within moments. Someone who reads their calendar in Apple Calendar still sees those events if their Google or Outlook calendar is set up on their iPhone or Mac.

Some customers will want to know what they're agreeing to before they grant access. Our guide to what connected calendar apps can see answers that, and How did this event get in my calendar? helps a customer who finds an event and can't remember where it came from.

Will events in their calendar get people to show up?

The reminder studies we found tested texts, letters, emails and phone calls, and none of them tested calendar events, as our look at whether reminders reduce no-shows sets out. Our comparison of reminders by calendar, email, text and app push covers what each channel asks of customers. To judge any of them, count clicks and attendance. Email opens overcount Apple Mail readers, for reasons our guide to Apple Mail Privacy Protection explains.

Where TheyCal fits

We make TheyCal, and it uses the last two options. Customers follow a business once from its join page, which the business can share as a link or a QR code. Google and Microsoft users connect their calendar, and TheyCal adds the business's events to it and updates or removes them whenever the business makes a change. The events go in as the customer's own entries, without an invitation email or a guest list, and show as free time so nobody looks busy because of them.

People on Apple Calendar and other apps confirm their email and get a private calendar link of their own, which suggests an hourly refresh to their app. Followers pick which kinds of events they want, and a business can also send an event to one person, such as a service reminder timed from their car's last service.

A business's TheyCal join page, offering Google, Microsoft Outlook, and Apple Calendar and others — On a TheyCal join page, people pick the calendar they use.

Common questions

Can I put events on customers' calendars without asking them?

With the other three options the customer acts first. An invitation can land on a calendar before the customer has agreed to anything, depending on their calendar settings, and an event they don't expect can look like spam.

Do customers need to install an app?

Each option puts events in the calendar app they already use.

What happens when a customer stops following?

In TheyCal, the business's upcoming events come off their connected calendar. With a calendar link, they drop out when the app next refreshes it.

Which option should a small business start with?

For a single event that won't move, a button is enough. For a schedule that grows or changes, ask customers to subscribe or connect, so each new event reaches them without another tap.