Yes, you can share free/busy availability with Google Calendar, Outlook, and Microsoft 365.
No, you’re not the only person confused by the difference between calendar sharing and free/busy sharing.
In short, most calendar platforms support free/busy scheduling, but the setup process, permissions, and visibility settings can vary from one system to another.
👉 We’ll also compared Google Calendar vs Outlook Calendar in detail.
How to Use a Free Busy Calendar with SyncThemCalendars
With SyncThemCalendars, you can control whether synchronized events should block your availability in the target calendar or not, thanks to two complementary features:
- the Availability setting,
- the new “busy” event filtering system.
The “Availability” Setting
The Availability setting lets you define how an event from the source calendar appears in the target calendar from an availability perspective.
There are two possible statuses:
- Busy: an event marked as busy blocks the time slot and prevents appointments from being scheduled. It indicates that you are unavailable.
- Free: an event marked as free remains visible in the calendar, while keeping the time slot available for scheduling meetings or appointments.
Example
You synchronize your personal calendar with your work calendar. You can choose to have all synchronized events displayed as free.
➡️ This way, your colleagues can see that you already have something scheduled, while still being able to book a meeting during that time slot if needed.
💡 Our fulls articles dedicated to the Availability setting, availables here and here, can help you better understand how it works. You might also be interested in our article on “How to filter events when syncing calendars.”
The “Busy” Filter
This new feature allows you to exclude certain events from synchronization based on a keyword found in their title. It is especially useful for creating busy slots.
Why Did We Create It? Because some users (Hi Gabriel 👋) wanted to:
- keep blocking time slots in a specific calendar,
- without having those time slots appear in other calendars.
Example:
Your Freelance calendar contains both client meetings and personal “busy” time slots.
Your Work and Personal calendars should receive the freelance meetings, BUT NOT the “busy” time slots.
How Does It Work?
Step 1: in your source calendar, add your events as usual.
For example: Client meeting, Design review, busy, Busy.
The busy events represent the time slots you want to keep only in that calendar.
Step 2: Go to the settings of the relevant synchronization, then look for the Filters section.
Step 3: Add the Keyword to Exclude.
In Filters, add the keyword “busy”. All events whose title contains this keyword will not be synchronized to the target calendar.
Step 4: check the Result. After synchronization:
✅ Events like Client meeting or Design review will be synchronized.
❌ Events containing busy in their title will be ignored.
💡 Important: filters are case-sensitive. Filters distinguish between:
- busy,
- Busy,
- BUSY.
These are three different values. So depending on how you name your events, you may need to add several variations.
How to Use Free Busy in Google Calendar
In 2026, with Google Calendar, the “free/busy” system still works on the same basic principle. You can share:
- either just your availability (“Free” / “Busy”);
- or more information about your events, such as their titles, times, or specific details, depending on the permission level granted.
How do you do it?
Step 1: Open Google Calendar.
Go to https://calendar.google.com
Sign into your Google account.
Step 2: Open Calendar Settings. In the left sidebar:
- find your calendar,
- click the three dots,
- Select “Settings and sharing”.
Step 3: Scroll to: “Share with specific people or groups”.
Click “Add people and groups”.
Enter a Gmail address.
Step 4: Choose the Correct Permission Level.
Select “See only free/busy” (hide details). This allows people to:
- check your availability,
- schedule meetings,
- avoid conflicts,
without accessing private information.
💡 Good to know: In Google Workspace, an administrator can prevent external sharing, certain visibility levels, and free/busy access outside the organisation.
How to Use Free Busy in Outlook and Microsoft 365
In principle, it is very similar to Google Calendar. However, there are also significant differences, as Microsoft 365 / Outlook / Exchange has historically been more business-oriented, and is therefore more heavily managed and more complex.
Quick Version
With Outlook / Microsoft 365:
- Open your calendar.
- Go to the sharing settings.
- Add a person.
- Select Can view when I’m busy.
- They will be able to see your availability, but not the event details.
- The Scheduling Assistant then uses this information to find a suitable time slot for everyone.
Full Version
Step 1: Open Outlook Calendar, then go to your Calendar. You can do this from:
- Outlook on the web,
- the new Outlook,
- Outlook desktop.
Step 2: In the calendar view, look for “Share Calendar” or “Sharing and permissions”.
Step 3: Add the person you want to share with:
- Enter their email address or name,
- Select the correct contact from the list.
Step 4: Choose how much detail the person can see:
- Can view when I’m busy → availability only.
- Can view titles and locations → limited details.
- Can view all details → full visibility.
Step 5: Use Scheduling Assistant to find a meeting time.
- Create a new meeting.
- Add attendees.
- Open Scheduling Assistant.
- Outlook checks everyone’s availability.
- You choose a time slot where people are free.
Step 6: Check event status: Free or Busy.
Each calendar event can affect your availability.
- If an event is marked as Busy, it blocks your calendar.
- If it is marked as Free, people may still see you as available.
So for important meetings, appointments, focus time, or travel time, make sure the event is marked as Busy.
FAQ
What Should I Enter in the Minimum Time and Maximum Time Fields?
The Minimum Time and Maximum Time fields define the time range in which the system searches for available meeting slots. These settings help:
- avoid scheduling meetings too early or too late,
- match working hours,
- reduce unnecessary scheduling conflicts.
The exact availability results may vary slightly between Google Calendar and Microsoft 365 because each platform handles calendar statuses and permissions differently.
Is Creating a Public “Busy” Calendar a Good Idea?
Technically, yes, some users create a separate public “Busy” calendar that automatically mirrors availability from their private calendars.
However, this approach can quickly become difficult to maintain. Using scripts or custom automations may introduce:
- synchronization delays,
- permission issues,
- duplicate events,
- timezone inconsistencies,
- and additional maintenance work.
In most cases, using a dedicated availability management tool like SyncThemCalendars is significantly simpler. Instead of maintaining a separate public “Busy” calendar manually, SyncThemCalendars can automatically synchronize availability across multiple calendars while keeping private event details hidden.
What is busy and free in Google Calendar?
In Google Calendar, every event can be marked as either Busy or Free. This setting controls whether the event blocks your availability for meeting scheduling.
What is the best free calendar to use?
The best free calendar depends on your needs.
Google Calendar is usually the best option for personal use and simple collaboration.
Outlook / Microsoft 365 is better for business and enterprise scheduling.
Apple Calendar works well inside the Apple ecosystem.
How to show free busy in Outlook calendar?
Open your Outlook calendar, go to Sharing and permissions, then select “Can view when I’m busy”. This shares your availability without exposing private event details. See the detailed tutorial above for the full setup process.
What does "show as busy or free" mean on an iPhone calendar?
On iPhone Calendar, the “Show As” setting controls whether an event blocks your availability.
- Busy means other people may see you as unavailable during that time.
- Free means the event stays on your calendar, but you still appear available for scheduling.
What Is the Difference Between Calendar Sharing and Free/Busy Sharing?
Calendar sharing and free/busy sharing are not the same thing.
Free/Busy sharing : only shows whether you are:
- available,
- busy,
- or unavailable.
People can see your availability, but not your private event details.
Calendar sharing can give access to:
- event titles,
- meeting details,
- locations,
- notes,
- attendees,
- or even editing permissions.
The exact visibility depends on the permission level you choose.
In short:
- Free/busy sharing = availability only.
- Calendar sharing = access to calendar content.
