For regular event reminders, calendar reminders are significantly cheaper and often more effective than SMS. For last-minute urgent alerts, SMS still has a role.

The cost gap is substantial

A marketing team running weekly fitness classes for 500 members:

• SMS reminders at $0.03/text: $15/class × 52 weeks = $780/year - just for reminders, before any other SMS spend
• Calendar reminders via AddEvent: $0 per reminder - the attendee's device handles all notifications after the event is added once

At scale, the gap grows. 2,000 attendees × weekly reminders = over $3,000/year in SMS costs. Calendar reminders at the same scale cost nothing extra.

Why calendar reminders often outperform SMS

Timing - calendar alerts fire at the moment they're most useful (1 hour before the event). An SMS reminder sent the day before competes with dozens of other texts for attention.

Persistence - the event sits visibly on the person's schedule every day until it happens. A text message is read once and disappears into the message thread.

Detail - the calendar event contains all relevant information - location, Zoom link, description - right where the reminder fires. An SMS reminder typically just contains a short message with a link the user must click.

No opt-out friction - once a user adds your event to their calendar, they receive all reminders their calendar app generates automatically. SMS requires explicit opt-in and has opt-out rates that grow with frequency.

When SMS is the better choice

Last-minute changes (venue moved, session cancelled, new information) where immediacy matters more than cost. SMS cuts through immediately; a calendar update may take 12–24 hours to sync. Use SMS as a complement to calendar reminders for urgent exceptions, not as your primary reminder channel.