Carbon
Copy events between calendars.
Carbon copies events from one calendar to another, so time blocked in one shows up in the other. Point it at a source and a destination, choose what to copy, and Carbon keeps the destination in step.
- iPhone and iPad
- iOS 18 or later
- Free for 30 days
- One purchase, no subscription
What it does
One way, always
Carbon copies from a source calendar to a destination. It never writes back to the source. Your work calendar stays exactly as your employer's system left it.
Choose what crosses over
Copy full event details, or copy only a "Busy" placeholder that reserves the time without revealing the title, location, or notes. This is set per mirror, so a sensitive work calendar and a shared family calendar can be handled differently.
See it before it happens
Every new mirror shows a preview of exactly what will be created before anything is written to your calendar.
It won't touch what you've touched
Carbon only ever changes events it created. Edit one of its copies yourself and Carbon steps back and leaves it alone, permanently.
Undo any sync
Sync history shows every run. Reverse any one of them and the events it created are removed.
Filters that keep the noise out
Skip all-day events, skip invitations you declined, skip anything shorter than a set length, or exclude events whose titles contain particular words.
Two years ahead if you want it
Choose how far each mirror reaches, up to two years ahead and a year back. Keep the window narrow for quicker syncs, or open it up so next year is already blocked out.
Privacy
No account. No server. No analytics. Everything stays on your device, and Carbon has no way to send your calendar anywhere. The only thing it ever sends is your purchase, to Apple. Carbon's App Store listing reports Data Not Collected in every category.
See the privacy policy for the full statement.
Good to know
When Carbon syncs
Carbon syncs when you open it, and periodically in the background when iOS allows. iOS decides how often background refresh happens, and it can be infrequent. For syncs on a schedule you control, add Carbon's "Sync Calendars" action to a Shortcuts automation. Carbon walks you through it.
Invitations
iOS does not allow apps to add attendees to an event, so copies are standalone events without invitees. This is an iOS limitation, not a Carbon one.
Work calendars
Some employers restrict copying work calendar data to personal accounts, and managed accounts may block access entirely. Check your organization's policy.
Support
Questions, bug reports, and feature requests go to [email protected]. The support page lists what to include when reporting a problem.