Add busy blocks from your work calendar to your personal calendar

Copy your work calendar into your personal calendar as busy blocks, and your personal calendar into your work calendar the same way. Each side then shows when you're busy on the other, without the details. Evenings get planned around late meetings, and coworkers don't book over the dentist.

Why the built-in options fall short

Free/busy sharing works inside one provider, and work accounts usually share only within the organization.
Subscribing to a published link gets you a read-only view. A subscribed calendar doesn't count toward your availability, so scheduling tools still show you as free.
Copying appointments by hand works until something moves.

Work to personal

Busy blocks from work tell your personal calendar, and anyone you share it with, when you're tied up. Each meeting becomes a block of time under a title you choose, like "Work", with no meeting name, location or notes. Company policies vary, so check yours before copying work details to a personal calendar. Busy blocks share only times.

Personal to work: the reverse direction

This is the direction that protects your time. A personal appointment copied into your work calendar as a block marked Busy counts toward your free/busy time, so when a coworker looks for a slot, the dentist is already taken. With the title replaced by something like "Busy" or "Personal", they see the time and nothing else.

In this direction, turn on Skip all-day events so birthdays and holidays don't block your whole work day, and Skip events marked Free for placeholders that shouldn't count. Tag anything you want to leave out entirely with #nosync.

An example week

On Tuesday you have a review at work from 4 to 5 PM and a school concert at 6 PM in your personal calendar. After the sync, your personal calendar shows "Work" from 4 to 5, so nobody plans dinner then. Your work calendar shows "Busy" at 6, so a late call lands somewhere else. Coworkers never see the word "concert", and your family never sees what the review was about.

One sync or two

Set this up as one two-way sync or as two one-way syncs. In a two-way sync, each direction has its own rules, so both directions can be busy blocks with different titles.

Busy blocks are one-way by nature: if someone edits one, the next sync puts it back, and the original isn't touched. A copy is never copied again, so a work meeting that becomes a personal busy block won't bounce back into your work calendar as a second block.

Set it up with Syncom

1
Add your accounts to your Mac. In System Settings › Internet Accounts, add your work account and your personal one (iCloud, Google or another), with Calendars turned on.
2
Add a sync between them. From Syncom in the menu bar, add a sync with your work calendar on one side and your personal calendar on the other, and set it to go both ways.
3
Choose Busy blocks only for each direction. Apply the preset to each direction and set its title, such as “Work” for copies in your personal calendar and “Busy” for copies in your work calendar.

A week of work meetings in Outlook for Mac, color-coded, with titles and rooms — The original meetings, in Outlook.

The same week in Apple Calendar, where each meeting is a plain Busy block — The same week as busy blocks in Apple Calendar.

Recurring events copy correctly in both directions: move or cancel one meeting in a series, and only that block changes. Syncom syncs when a calendar changes, when your Mac wakes and when your VPN connects, while your Mac is on and you're logged in. Want a reminder on the other side too? Add an alert to the copies, at the start or up to 2 hours before.