SMS or email for appointment reminders

The useful question is not simply which channel has the better open rate. For an appointment reminder, you need to consider how much information must be sent, how soon the appointment is, the cost of each message and how easily the customer can cancel or reschedule.

Published healthcare research shows that automated reminders, including SMS, can improve attendance. It does not establish that SMS is always superior to email in every setting or that 24 hours is the universally best timing.

The practical difference between SMS and email

Neither channel guarantees that the customer will read the message. Automation and clear content therefore matter more than a blanket claim that one channel always wins.

A sensible starting pattern: email for detail, SMS for brevity

For many service businesses, this is a practical initial setup:

Booking confirmation by email. Include the address, useful instructions, cancellation terms, price and a link to manage the appointment.

Short SMS reminder. Include the business name, appointment date and time, and a cancellation or reschedule route. Keep it focused on the existing appointment.

This is a starting recommendation, not a universal rule. If your own customers reliably respond to email, there is no reason to add paid SMS merely because another business does.

Let timing follow your cancellation window

Instead of hard-coding “24 hours before” as a rule, start with the amount of notice you need to refill a cancelled slot. If free cancellation closes 24 hours before the appointment, a reminder sent after that point may be too late to help both the client and the business.

A randomised study of 54,066 healthcare appointments found that reminder number and timing can matter. The useful lesson is to test timing, not to copy one schedule across every industry.

For bookings made far in advance, you may test an earlier reminder followed by a shorter message nearer the date. For next-day bookings, an additional reminder may be unnecessary.

How to decide whether paid SMS is worth it

Do not assume a promised no-show reduction. Measure your own result.

1. Record no-shows and timely cancellations for several weeks without SMS.
2. Enable SMS for a comparable period.
3. Record the message cost.
4. Compare how many additional appointments were attended or refilled.

That produces an ROI based on your customer base rather than a research sample from a different country or industry.

What a short reminder should contain

A useful operational reminder should be easy to act on:

1. business name,
2. date and time,
3. service or provider where useful,
4. a clear cancellation or reschedule option.

Adding a promotion, discount or invitation to make another booking changes the purpose toward direct marketing. In Slovenia, electronic direct marketing is subject to specific ZEKom-2 rules as well as data-protection requirements; see GDPR for salons and service businesses.

What to configure in Calendra

Calendra lets you configure confirmations and reminders separately, including the channel, sending time and template content. See Appointment reminders for the product workflow.

Start simply: one confirmation and one reminder timed around your cancellation policy. Measure the result, then add a second reminder or change the channel only when your own data gives you a reason.

Sources and evidence limitation

The studies below are mostly from healthcare. They support appointment reminders as an attendance intervention; they do not prove that one channel is always best for salons or other service businesses.

• Cochrane/PubMed: mobile messaging reminders for appointment attendance
• Systematic review: SMS reminders and appointment attendance
• Randomised study: number and timing of appointment reminders
• Slovenian Information Commissioner: electronic direct marketing under ZEKom-2