You manage multiple Google Calendars. Work. Personal. Side projects. They’re scattered. Fragmented. You need to see everything in one place.
Most “sync” tools are either slow, expensive, or don’t actually sync both directions. We tested five tools that claim to do the job. Here’s what works and what doesn’t.
How We Evaluated These Tools
We tested each tool on five criteria that matter:
Free tier availability. Can you actually use it without paying? A limited free tier counts. A free trial doesn’t.
Sync speed. Minutes or seconds? We measured time from event creation in one calendar to appearance in the target calendar.
Privacy controls. Can you hide event details? Does the tool respect your privacy settings?
Platform support. Google Calendar only or does it handle Outlook, Apple Calendar, or others?
Setup and transparency. How many steps? Is pricing clear? Can you undo changes?
No tool scored perfect across all five. But some came closer than others.
1. SYNCDATE
Free tier: Up to 2 calendars. No credit card required.
Pricing: Starter €1.99/mo (9 calendars, 4 accounts), Pro €8.99/mo (30 calendars, 8 accounts).
SYNCDATE is a Google Calendar sync utility built for speed and privacy. It uses webhook-based sync, which means events appear in seconds—not minutes. The default mode shows events as “Busy,” hiding all details from the synced calendar. You get two-way sync or one-way. You can kill it anytime. All events are deleted cleanly.
Where it excels: You have work and personal calendars that need to stay separate but visible together. Two-way sync means changes in either calendar reflect instantly. The “Busy” privacy mode is the standard. You see availability without exposing details.
Specific use case: A freelancer with multiple client calendars and a personal calendar needs to block personal time on each client’s schedule (so they don’t double-book). One-way sync from personal to each client calendar, set to “Busy.” They see blocked time but not what you’re doing.
Limitation that matters: Supports Google Calendar and Microsoft Outlook/Office 365 via the Microsoft Graph Calendar API. iCloud is not yet supported. The free tier stops at 2 calendars, which works for simple cases but breaks down fast.
Infrastructure: EU hosted on Hetzner Germany, GDPR compliant. OAuth 2.0 tokens encrypted with AES-256. Backup polling every 15 minutes.
Setup time: 3-4 minutes. Authorize Google, select calendars, set sync direction.
2. OneCal
Free tier: 2 calendars. Free trial available.
Pricing: €2.99/mo - €14.99/mo depending on features.
OneCal combines calendar syncing with scheduling and meeting notes. The calendar sync is solid but it’s bundled with features you might not need.
Where it excels: If you want to sync calendars and you want a scheduling assistant in the same tool, OneCal consolidates those jobs. The interface is clean. Syncing is reliable, though not as fast as webhook-based solutions.
Specific use case: A sales rep who manages a work calendar, personal calendar, and needs to auto-generate availability links for client meetings. OneCal handles sync plus scheduling in one place.
Limitation that matters: Pricing tier mapping is unclear. You start free with 2 calendars, but the jump to 3+ calendars requires a paid plan. No transparency on what each tier actually includes. You might think you’re in a free plan and hit a limit unexpectedly.
Privacy controls: Events are visible by default when synced. You need to manually adjust privacy settings on individual events. Not automatic.
Sync speed: Polling-based. Expect 3-10 minute delays. Not real-time.
Setup time: 5-7 minutes plus privacy configuration on events.
3. Reclaim.ai
Free tier: Limited to 1 calendar pair. Free trial available.
Pricing: $10/mo - $25/mo.
Reclaim.ai is a time management tool that includes calendar syncing as one feature. It’s focused on blocking focus time, syncing calendars, and managing meeting loads.
Where it excels: If you’re fighting calendar chaos across multiple calendars and you want intelligent meeting scheduling, Reclaim can handle both. It learns your patterns and suggests optimal meeting windows.
Specific use case: A manager with work, personal, and recruiting calendars. Reclaim syncs all three, then intelligently blocks focus time and prevents back-to-back meetings across all calendars.
Limitation that matters: The free tier only syncs 1 calendar pair. Add a second pair? Paid plan required. For most multi-calendar users, free doesn’t cut it. The pricing is also at the premium end.
Privacy: Events are visible when synced. You set privacy per-event.
Sync speed: Polling-based. 5-15 minute delays typical.
Setup time: 5-8 minutes, but configuration is more complex due to focus time and meeting load settings.
4. CalendarBridge
Free tier: None.
Pricing: Basic $4/mo (2 calendars), Premium $8/mo (5 calendars).
CalendarBridge is a sync-focused tool supporting Google, Outlook, and iCloud. No free tier, but pricing is straightforward.
Where it excels: Multi-platform support. If you need Google + Outlook + iCloud in one sync tool, CalendarBridge handles it. Simple setup, no extra features.
Specific use case: A student with a personal Google Calendar and a university Outlook calendar. CalendarBridge syncs both directions across platforms.
Limitation that matters: Sync is polling-based. 5–15 minute delays are normal. No free tier — you pay from day one. For Google-only users, SYNCDATE is faster (webhooks vs polling) and has a free tier.
Privacy: Events appear with details by default. Privacy controls exist but aren’t automatic.
Sync speed: Polling every 5–15 minutes.
Setup time: 3-4 minutes. Minimal configuration.
5. SyncGene
Free tier: Up to 2 calendars. No credit card.
Pricing: $6/mo - $15/mo.
SyncGene is an older tool in the space. It works, but it’s being phased out in favor of newer options. Still functional if you just need basic sync.
Where it excels: If you’re already using it and it works, there’s no emergency to switch. Sync is reliable even if slow.
Specific use case: Small teams where each person manages a personal and work calendar. SyncGene handles 1:1 sync adequately.
Limitation that matters: Development is slow. Updates are rare. If something breaks, support is sluggish. The ecosystem is mature but not improving. Also, no two-way sync—only one direction. If you need bidirectional updates, this won’t work.
Privacy: Details are visible. No automatic privacy masking.
Sync speed: Polling-based. 15-30 minute delays common.
Setup time: 4-5 minutes.
Honorable Mentions
These tools almost made the list. Here’s why they didn’t.
SyncThemCalendars
SyncThemCalendars supports multiple platforms (Google, Outlook, Apple). Sounds good. But there’s no free tier. Minimum €5/mo. For Google-to-Google sync, you’re paying for platform support you don’t need. Also, the company is less transparent about where data lives or how encryption works.
The tradeoff: Multi-platform support costs money and privacy clarity suffers.
See SyncThemCalendars alternative.
IFTTT
IFTTT is a general automation platform. You can create “if event created in Calendar A, create event in Calendar B” workflows. But it’s not true sync. It only handles new events. Updates don’t sync. Deletions don’t sync. It’s one-way and incomplete. Also slow—5-30 minute delays.
The tradeoff: It’s a workaround, not a solution.
See IFTTT Google Calendar sync.
Zapier
Zapier is similar to IFTTT. It can copy new events from one calendar to another, but it’s a one-way workflow, not sync. Updates and deletions are ignored. You’ll end up with duplicate events and missed changes. Also expensive for this specific job—$20-$600/mo depending on tier.
The tradeoff: Overkill for calendar sync. Better for different integrations.
What to Look For in a Calendar Sync Tool
Before you choose, ask these questions:
1. Does it sync both directions or just one way?
True sync means changes in either calendar appear in the other. One-way copy means one calendar is the source. One-way works if you have a hub calendar (personal) and spokes (work, projects). True two-way sync works if you need real-time updates from both sides.
2. Does it auto-hide sensitive details?
Privacy matters. Look for “Busy” mode or automatic event masking. If you have to manually set privacy on each event, you’ll forget. Automatic is safer.
3. How fast is the sync?
Seconds? Minutes? If you’re syncing multiple calendars daily, polling every 15 minutes is acceptable. If you need real-time blocking (to prevent double-booking), webhook-based sync matters.
4. Can you undo it?
If you disconnect the sync, what happens? Are events deleted cleanly or do they linger? Clean rollback means you can test risk-free.
5. Is pricing transparent?
A free tier with clear limits is honest. A “free trial” that converts to paid is a trap. Tiered pricing that scales with calendar count is fair.
Comparison Table
| Tool | Free Tier | Speed | Privacy | Two-Way | Setup |
|---|---|---|---|---|---|
| SYNCDATE | 2 calendars | ~4 sec (webhook) | Busy mode auto | ✓ | 3-4 min |
| OneCal | 2 calendars | 3-10 min | Manual | ✓ | 5-7 min |
| Reclaim.ai | 1 pair | 5-15 min | Manual | ✓ | 5-8 min |
| CalendarBridge | None | 5-15 min | Manual | ✓ | 3-4 min |
| SyncGene | 2 calendars | 15-30 min | Manual | One-way | 4-5 min |
| SyncThemCalendars | None | 2-5 min | Manual | ✓ | 5-6 min |
FAQ
Can I sync more than 2 calendars for free?
SYNCDATE and OneCal offer 2 calendars free. SyncGene offers 2 free. CalendarBridge has no free tier (starts at $4/mo). If you need 4+ calendars, you’ll need a paid plan across all tools.
Will syncing calendars slow down Google Calendar?
No. Calendar apps are lightweight. The sync operation happens in the background. You won’t notice performance impact.
Can I sync personal and work Google accounts without sharing passwords?
Yes. All these tools use OAuth 2.0, which means you authorize access without sharing passwords. You can review and revoke access anytime at Google Account permissions. Each account authorizes separately.
What happens if I delete an event from one calendar?
If two-way sync is active, the event is deleted from the other calendar too. If one-way sync, only the source calendar controls deletions.
Can I sync to multiple destinations from one source?
Yes. You can set up separate syncs. Example: Personal calendar syncs to Work calendar AND Client calendar. This requires one-way syncs or multiple two-way pairs.
What’s the cheapest way to sync 5 Google Calendars?
Hub-and-spoke method: Pick one as the hub (usually personal). Sync the other 4 one-way to it. This requires 4 sync connections. SYNCDATE Starter at €1.99/mo covers 9 calendars across 4 accounts — that’s the cheapest option for Google-only users. CalendarBridge starts at $4/mo for 2 calendars, so 5 calendars would require their $8/mo Premium plan.
Choose Based on Your Needs
If speed matters and privacy is important: SYNCDATE. Webhook-based sync, automatic privacy, two-way, clean exit.
If you need Google + Outlook sync: SYNCDATE now supports both platforms via the Microsoft Graph API. Alternatively, CalendarBridge starts at $4/mo with multi-platform support including iCloud.
If you need scheduling plus sync: Reclaim.ai. More expensive, but handles both jobs in one tool.
If you’re already using OneCal or SyncGene: They work. No emergency to switch.
If you need multi-platform (Outlook, Apple): SyncThemCalendars. But you’ll pay for it and give up some privacy clarity.
Related: [Sync two Google Calendars](/blog/sync-two-google-calendars), [Sync personal and work Google Calendar](/blog/sync-personal-work-google-calendar), [Sync multiple Google Calendars](/blog/sync-multiple-google-calendars), [Google Calendar sharing vs syncing](/blog/google-calendar-sharing-vs-syncing), [Avoid double-booking Google Calendar](/blog/avoid-double-booking-google-calendar), [Is it safe for Google Calendar apps to access your account?](/blog/is-it-safe-google-calendar-app-access), [Best calendar sync tool comparison](/compare/best-calendar-sync-tool-comparison), [OneCal alternative](/compare/onecal-alternative), [Reclaim alternative](/compare/reclaim-alternative), [CalendarBridge alternative](/compare/calendarbridge-alternative), [SyncThemCalendars alternative](/compare/syncthemcalendars-alternative), [IFTTT Google Calendar sync](/compare/ifttt-google-calendar-sync)