The Best Outlook Google Calendar Sync (OGCS) Alternatives in 2025

Outlook Google Calendar Sync (OGCS, in short) is an open-source Windows application that users install on their device, primarily used to synchronize Outlook and Google Calendars.

In this article, we’ll list the best Outlook Google Calendar Sync (OGCS) alternatives, highlighting all the features, the similarities, and differences they have with OGCS.

Why do users look for alternatives to Outlook Google Calendar Sync (OGCS)?

Users look for Outlook Google Calendar Sync (OGCS) alternatives because of the following reasons:

• Windows only: Outlook Google Calendar Sync (OGCS) can only be used on Windows devices. Although Windows has a 70% market share of desktop operating systems worldwide, many professionals prefer Mac or Linux as their operating system of choice. Furthermore, the device is subject to the actual job, and can change over time.
• No support for iCloud Calendars: OGCS used to struggle with connecting to a Microsoft 365 cloud account, but has recently published a new version that doesn’t require the Outlook client to connect your Outlook accounts to OGCS. That said, OGCS doesn’t have support for iCloud Calendars to date.
• Requires the app to be running for the sync to continue: OGCS is a Windows app, the service runs only when the app is running. If you close the app, or you forget to keep it open, your calendars will stop synchronizing. This is not ideal, as there are scenarios such as the laptop shutting down due to low battery or other factors that keep your calendars out of sync.
• Outdated UI and UX: Although UI and UX may not be the most important factors when choosing a calendar synchronization app, the OGCS user interface and experience are very similar to those of Windows 7.

What are The Best Outlook Google Calendar Sync (OGCS) Alternatives You Should Consider in 2025?

1. OneCal

OneCal is the best cloud-based calendar synchronization platform, integrating with Outlook, iCloud, and Google Calendars and featuring a reliable, real-time calendar synchronization platform.

What differentiates OneCal from OGCS?

• Cloud-based: You don’t need a specific type of device to use OneCal. As long as you have access to the internet, you can use your browser to access OneCal. No apps to install, no installation guides needed.
  
• Synchronization that happens in the background: Unlike OGCS, OneCal doesn’t require you to keep anything open for your calendars to stay in sync. After you set up your calendar synchronization configuration, OneCal keeps your calendars in sync in real-time. No periodic synchronization, and no need to keep any applications open. Regardless of whether you change devices or your device stops working, you can be confident that OneCal is keeping your calendars in sync.
• Support for iCloud: OneCal is approved by Microsoft and Google, securely connects to your calendars, and also integrates with iCloud, keeping all your iCloud calendars in sync.
• Support for multi-way synchronizations: Although Outlook Google Calendar Sync (OGCS) has support for two-way syncs, OneCal takes it up a notch with multi-way syncing. With OneCal, you can sync multiple calendars in one sync configuration (not limited to 2 calendar sync as in OGCS). For example, if you want to sync five calendars, you can do so with a single sync in OneCal. Using OGCS, you’ll need 20 one-way calendar sync configurations.
  
• Scheduling Links: Aside from the Calendar Sync feature, OneCal also offers a scheduling links feature, allowing you to share personalized links that others can use to book meetings with you. You can customize the look and feel of the scheduling links to match your brand, ask custom questions, set limits, reminders, and much more.
  
• Calendar View: You can view all your calendars across all platforms using OneCal Calendar View. There is no need to switch between different calendar clients, you can only use one view for all your calendars connected to OneCal.
  
• Invite team members: You can invite your team members to OneCal, share collective scheduling links, and use the Calendar View to see your team members’ availability. Note that, unlike in Google Calendar or Outlook, with OneCal, you can view the combined availability of your team members, as our Calendar View considers all calendars from all providers.
• Amazing customer support team: Although the features are important, having a customer support team that helps you with any issues you have is equally important. OneCal and the customer support team have outstanding reviews.
  

What do OneCal and Outlook Google Calendar Sync (OGCS) have in common?

• Integration with Outlook and Google Calendar.
• Calendar Synchronization: Although the philosophy is different, Windows-based vs. cloud-based, in essence, both platforms synchronize calendars.

2. Sync2

Similar to OGCS, Sync2 is a downloadable PC application that allows you to synchronize Outlook data, including calendars, email, and contacts, on multiple PCs. Sync2 also allows you to sync Outlook Calendar with Google Calendar without a server.

What differentiates Sync2 from Outlook Google Calendar Sync (OGCS)?

• OGCS is open-source: Although Sync2 is a downloadable PC application, OGCS is open-source, and you can contribute to it if you wish.
• Sync2 requires the Outlook client running: The newest OGCS application version doesn’t require having the Outlook client running on your PC to connect your calendars. Sync2, on the other hand, requires running Outlook 2007, 2010, 2013, 2016, or 2019.
• OGCS is free: You can use OGCS for free; Sync2 requires a license.
• Sync2 has support for iCloud calendars: Unlike OGCS, Sync2 has support for iCloud calendars.
• Sync2 can sync tasks, emails, calendars, and contacts.

What do Sync2 and Outlook Google Calendar Sync (OGCS) have in common?

• Need to be installed on your PC: Both OGCS and Sync2 need to be installed on your PC in order to work.

3. Reclaim AI

Reclaim is an AI Calendar app that helps users organize their time, sync their calendars, and share scheduling links.

What differentiates Reclaim AI from Outlook Google Calendar Sync (OGCS)?

• Cloud-based vs Windows-based: Similar to OneCal, you don’t need to install Reclaim on your device.
• Background Calendar Synchronization: Unlike OGCS, Reclaim AI doesn’t need the application running to sync your calendars.
• AI features: Reclaim AI is much more than a calendar synchronization tool, as it offers features like focus time, scheduling links, auto-schedule breaks after meetings, and more.
• Superior user interface: Reclaim AI is a web app with a modern look and feel. You can quickly connect your calendars and sync them, as well as use other AI-related features.

4. SyncGene

SyncGene is a cloud-based application that can synchronize contacts, calendars, and tasks between Google, Outlook, and iCloud.

What differentiates SyncGene from Outlook Google Calendar Sync (OGCS)?

• No need to install anything on your PC: Like OneCal and Reclaim, SyncGene is cloud-based, you don’t need to install anything on your PC in order to sync your calendars.
• Support for iCloud Calendars: SyncGene integrates with iCloud, allowing you to sync calendars across all major providers.
• Runs in the background: SyncGene is cloud-based and doesn’t need to be kept open or running for it to keep syncing your calendars.
• More integrations: SyncGene has more integrations than OGCS, including Salesforce, Samsung, and more.

5. Zapier

Zapier is an automation platform that integrates with hundreds of platforms and can be used to build your own automation. You can connect your calendars to Zapier and configure a one-way sync.

What differentiates Zapier from Outlook Google Calendar Sync (OGCS)?

• Zapier is cloud-based: Unlike OGCS, you can use Zapier on the web without installing anything on your device.
• Zapier integrates with more providers: Zapier is the largest automation platform in the market and integrates with hundreds of providers, including the major calendar providers like Google Calendar, iCloud, Microsoft Outlook, and more.
• Zapier doesn’t support two-way or multi-way syncs: Although you can use Zapier to sync a calendar to another, you can’t do two-way syncing. Zapier workflows are one-way; if you create multiple syncs between two or more calendars, you might trigger an infinite loop.
• Zapier doesn’t allow you to choose what to sync between calendars. With Zapier, you can clone events from one calendar to another as they are; you don’t have the options available in OGCS to strip out event titles, descriptions, etc.

Which Outlook Google Calendar Sync (OGCS) alternative is the best for syncing calendars?

OneCal is the absolute best Outlook Google Calendar Sync (OGCS) alternative in the market, offering everything that OGCS has to offer, and more.

The calendar synchronization is real-time, automatic, and doesn’t require any application to run in order to work.

With OneCal, you can sync multiple calendars in one configuration, without the need to create separate one-way syncs as with OGCS.

OneCal is not just a calendar sync tool, you can leverage the scheduling links to get booked externally without exposing your private information and view all your calendars in one view, regardless of the calendar provider.

Sync All Your Calendars Using OneCal

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FAQ

What is Outlook Google Calendar Sync (OGCS) used for?

Outlook Google Calendar Sync (OGCS) is a Windows application used to synchronize Outlook and Google calendars.

Does OGCS sync my calendars if I close the app?

No. The OGCS app needs to be open and running on your device for the calendars to stay in sync.

Which OGCS alternatives keep syncing in the background without an app open?

Cloud-based options like OneCal keep syncing even if your device is off. OneCal runs entirely in the cloud and maintains real-time calendar synchronization.

Which OGCS alternatives support iCloud calendars?

OneCal, SyncGene, and Sync2 support iCloud calendars.

What’s the best OGCS alternative in 2025?

OneCal is the best OGCS alternative, offering real-time, background calendar sync, multi-way support, plus extras like Scheduling Links and a unified Calendar View.

How fast do changes sync when using OGCS?

It varies, as OGCS polls at intervals. For real-time calendar synchronization, we recommend using cloud-based apps that update calendars in real-time.