How to Add SMS Reminders to Calendly Appointments
Send automatic SMS reminders for Calendly bookings using Remindlo and Google Calendar. Works with any Calendly plan, including free.
Calendly is a great tool for managing bookings, but if you want to send SMS reminders to clients before their appointments, you will quickly run into limitations with Calendly's built-in text messaging. This guide shows you how to add reliable, two-way SMS reminders to any Calendly booking - even if you are on Calendly's free plan.
The method is simple: Calendly already syncs events to Google Calendar. Remindlo monitors your Google Calendar and automatically sends SMS reminders for every appointment that includes a phone number. No extra integrations to build, no coding required.
What You Need
A Calendly account (any plan, including free).
A Google account with Google Calendar.
A Remindlo account - create one for free.
Calendly connected to Google Calendar (we cover this below).
How Calendly's Built-in SMS Works - and Its Limitations
Calendly offers text message reminders through its Workflows feature. Here is what you should know before relying on it:
Paid plans only - SMS is not available on Calendly's free plan or during the trial period. You need at least the Standard plan ($10/seat/month).
Limited credits - You get 250 SMS credits per seat per month (1,000 on Enterprise). Each message costs 1–9 credits, depending on the country.
No top-ups - When your credits run out, Calendly falls back to email. You cannot purchase additional credits. The only workaround is adding more seats to your account.
Random sender numbers - Messages are sent from randomly assigned US phone numbers via Twilio. Your clients see an unknown number, which can cause confusion or lead to messages being ignored.
No replies - Calendly's text messages are one-way only. If a client replies to the reminder, the response goes nowhere. You will never see it.
180-character limit - Each message is capped at 180 characters, which limits what you can include.
Phone number field is optional - Calendly cannot make the phone number question mandatory on booking forms due to SMS regulations. Invitees can also opt out later.
Host-booked appointments - When you book an appointment on behalf of a client, there is no way to add their phone number for SMS reminders.
These limitations are manageable for some businesses, but if you need reliable, recognisable SMS reminders with two-way communication, there is a better approach.
The Alternative: Calendly → Google Calendar → Remindlo
Here is how it works:
Calendly syncs events to Google Calendar - this is a built-in Calendly feature available on every plan.
Remindlo monitors your Google Calendar - it automatically detects new events and reads phone numbers from the event details.
SMS reminders are sent automatically - Remindlo sends personalised text reminders before each appointment, from a dedicated phone number.
This approach works with any Calendly plan, has no credit limits, and gives your clients a recognisable sender number they can reply to.
Method 1: Connect via Google Calendar Integration
This is the recommended approach. It takes about 5 minutes to set up, and then everything runs on autopilot.
Step 1: Connect Calendly to Google Calendar
If you have not already done this:
Log in to your Calendly account.
Go to Integrations in the top menu.
Find Google Calendar and click Connect.
Authorise Calendly to access your Google Calendar.
Select which calendar to sync events to.
Once connected, every new Calendly booking will automatically appear as an event in your Google Calendar. Cancellations sync too.
Step 2: Capture Phone Numbers in Calendly
For SMS reminders to work, Remindlo needs a phone number in the calendar event. Calendly includes invitee information in the event description, so you need to make sure a phone number is collected:
Go to your Event Types in Calendly.
Edit the event type you want to add SMS reminders to.
Under Booking Form, add a Phone Number question.
Mark it as Required so every booking includes a number.
When an invitee books, their phone number will be included in the Google Calendar event description - exactly where Remindlo looks for it.
Step 3: Connect Google Calendar to Remindlo
Follow our detailed guide to connect your Google Calendar to Remindlo:
→ How to Integrate SMS Reminders into Google Calendar
The guide covers connecting your calendar, enabling autopilot, and customising your reminder messages with dynamic variables like {{first_name}} and {{business_name}}.
Step 4: Done - Remindlo Handles the Rest
Once connected, Remindlo runs on autopilot. For every new Calendly booking that includes a phone number, Remindlo will automatically:
Detect the event in your Google Calendar.
Extract the client's phone number from the event details.
Schedule SMS reminders based on your configured timing (e.g. 24 hours before, 2 hours before).
Send personalised text messages from a dedicated phone number.
Remove scheduled reminders if the event is cancelled.
Method 2: Use the Remindlo Google Calendar Add-on
If you prefer more hands-on control, you can use the Remindlo sidebar plugin directly in Google Calendar. This add-on lets you:
Manually assign contacts to events.
Set a default country prefix for phone number normalisation.
Choose which campaign each event type belongs to.
For setup instructions, see the add-on section of our Google Calendar guide:
→ Google Calendar Add-on (Sidebar Plugin) Setup Guide
Comparison: Calendly Native SMS vs Remindlo
Feature | Calendly Native SMS | Remindlo via Google Calendar |
|---|---|---|
Calendly plan required | Standard ($10/seat/mo) or higher | Any plan, including free |
Monthly SMS limit | 250 credits/seat (no top-ups) | Plan-based, no credit system |
When limit is reached | Falls back to email | N/A - no credit limits |
Sender number | Random US phone number | "Remindlo" as sender or always the same number |
Client replies | Not supported (no-reply) | Two-way - replies visible in dashboard |
Message length | 180 characters | Standard SMS length. Multiple segments supported |
Message personalisation | Basic variables | Rich templates with dynamic variables |
International support | Some carriers may block | International support |
Setup effort | Built-in toggle | One-time Google Calendar connection (~5 min) |
Tips and Best Practices
Send two reminders - one the day before and one a few hours before the appointment. This is the most effective pattern for reducing no-shows.
Include your business name - since Remindlo sends from a dedicated number, adding your business name in the message helps clients immediately recognise who is texting.
Use dynamic variables - personalise messages with
{{first_name}},{{business_name}}, and{{business_phone}}for a professional touch.Make the phone number required - in your Calendly event type booking form, set the phone number field as required so every booking captures a number.
Test with a sample booking - book a test appointment through your Calendly link using your own phone number to verify the full flow works before going live.
Coming Soon: Direct Zapier Integration
We are building a Zapier integration that will allow an even more direct connection between Calendly and Remindlo - without needing Google Calendar as a bridge. With Zapier, you will be able to trigger SMS reminders directly from new Calendly bookings.
The Google Calendar method described above will continue to work perfectly. The Zapier option will simply offer an additional route for businesses that prefer it. Note that the Zapier integration with Calendly requires a paid Calendly plan.
Troubleshooting
Calendly events not appearing in Google Calendar
Check that Calendly's Google Calendar integration is active - go to Calendly → Integrations → Google Calendar and verify the connection.
Make sure you selected the correct calendar for syncing.
New events may take a few minutes to appear. Wait and refresh your Google Calendar.
Phone numbers not detected by Remindlo
Ensure the phone number question is added to your Calendly event type's booking form.
Check that the number includes a country code (e.g. +44 for UK). You can set a default country prefix in the Remindlo Google Calendar add-on, so we'll add it automatically if that's missing.
Open the event in Google Calendar and check that the phone number appears in the event description.
Reminders not sending
Verify your Remindlo account is active, and the Google Calendar is connected.
Check the Remindlo dashboard for sync status and any error messages.
Make sure the event is far enough in the future for reminders to be scheduled (events in the past are ignored).
Wrong timezone on reminders
Confirm your timezone settings match in Calendly, Google Calendar, and Remindlo.
Calendly uses the invitee's timezone by default - check that this matches the calendar event.
Need Help?
If you run into any issues setting up SMS reminders for your Calendly appointments, contact us at [email protected]. We are happy to help you get everything connected.