SMS reminders are more effective. Email reminders are cheaper. Most operators should use both, in a specific sequence.
The data
Across multiple industries:
| Channel | Open rate | Read within 1 hour | No-show reduction |
|---|---|---|---|
| SMS | ~95% | ~90% | 30-50% |
| ~25% | ~10% | 5-15% |
SMS reminders are 2-3x more effective at reducing no-shows. The reason: phones are always within reach; email is checked at desk hours.
Cost comparison
Email reminders are essentially free (your email provider charges per email, but pricing for transactional email is $0.0001-$0.001 per send).
SMS reminders cost $0.01-$0.05 per message, depending on country and provider.
For a business doing 200 reminders per month:
- Email: ~$0.20 per month
- SMS: $2-10 per month
The cost difference is real but small relative to the no-show revenue saved.
When to use email only
Email-only reminders work when:
- Your services are low-stakes (free consultations, low-cost group classes)
- Your no-show rate is already under 5%
- Your customer base is professional (B2B advisors, software consultants — these customers do check email)
For everyone else, SMS is the right primary channel.
When to use SMS only
SMS-only reminders work when:
- Your customer base is consumer (salon, fitness, beauty, pet services)
- Your services are high-stakes or expensive
- Cost per reminder isn’t a constraint
When to use both (recommended)
For most service businesses, the right pattern is:
At booking confirmation:
- Email — formal record with all details, calendar attachment, business policies, rebooking link
- SMS optional — quick “Booked! See you Friday at 2pm” if the channel is enabled
24 hours before:
- SMS — short, personal: “Hi Jules, this is Maria from Looks Salon. See you tomorrow at 2pm. Reply YES to confirm.”
- Email — same content as backup
2 hours before:
- SMS only — “Reminder: appointment in 2 hours at Looks Salon. See you soon!”
This stack handles the trade-off: email for record-keeping, SMS for actual attention-getting.
How to write SMS reminders
Constraints: 160 characters or less. Personal, not template.
Good SMS:
Hi Jules — Maria from Looks here. See you tomorrow at 2pm for your cut. Reply YES to confirm or call (555) 123-4567 to reschedule.
Bad SMS:
APPT REMINDER: 2026-05-06 14:00 LOOKS-SALON ID#42891 Confirm? Y/N
The first reads like a person; the second reads like a machine.
How to write email reminders
Email has more space, so include:
- The customer’s name
- The service + date + time + duration
- The staff member assigned
- The address + parking info if relevant
- A Reschedule link
- A Cancel link
- The cancellation policy reminder
- A “What to bring” / “What to expect” line if relevant
But still keep it short — under 200 words.
What about WhatsApp / iMessage?
WhatsApp is bigger than SMS in many countries (India, Brazil, Mexico, much of Europe). Where it dominates, send reminders via WhatsApp Business API or Twilio’s WhatsApp channel.
iMessage routing happens automatically when SMS is sent to iPhone numbers — you don’t need to do anything special.
How Zedule handles it
Zedule sends:
- Booking confirmation: email (always) + optional SMS
- 24-hour reminder: email + SMS (per-event toggle)
- 2-hour reminder: SMS only (per-event toggle)
Operators bring their own SMTP (any email provider) and SMS provider keys. Reminder content is fully editable in the template editor.