If you don't use Gmail for email but need to sync Outlook Calendar with a smartphone, Outlook.com is an option. If you own your own domain name, Office 365 hosted Exchange offers a much better sync experience.
At this time, the only way to sync a calendar between Outlook (Windows desktop) and free Gmail email accounts that syncs both ways and allows you to create events in Outlook is using a utility. If you only need to view a calendar in Outlook and won't be adding appointments to it, you can subscribe the Google calendar in Outlook's File, Account Settings, Subscribed Calendars. This creates a read-only calendar in Outlook! (It also triggers send and receive errors which are harmless but annoying.)
Sync Outlook to Google Calendar, Contacts, Tasks! Two-way sync is enabled by default, or choose one way sync. Set the Auto Sync feature for every 15 minutes or manually sync on your own. Outlook Categories map to Google Groups One user-license is valid on up to 3 PCs. Free Trial Available.
G-Suite subscribers can use a sync utility provided by Google.
Microsoft is working on a "Microsoft Cloud" solution that will sync Gmail calendar & Contacts to Outlook using a Microsoft Exchange account. It is available in Outlook 2016 for Mac and the Outlook app for smartphones but is not yet available in Outlook for Windows.
You can use one of the following utilities to sync your Outlook calendar (and contacts) with Gmail.
Tools in the Spotlight
|CompanionLink for Google||Do you need a solution to sync Outlook and Gmail Calendar and Contacts when Gmail ends ActiveSync? CompanionLink keeps Microsoft Outlook and your Google account synchronized. Make changes in Outlook and those will update your Google account. And vice versa. Set the auto-sync feature to automate the entire process. CompanionLink works with any Google, Gmail, or Google Apps account.|
|Companionlink for Outlook||CompanionLink synchronizes Outlook data with phones and other supported desktop applications and web-based services (like Google). Companionlink supports all versions of Outlook, including Outlook 2013 32-bit and 64-bit, and Windows 10. Version 9|
|4Team Sync2 for Outlook||Sync Outlook using Sync2 for Microsoft Outlook without a server. Sync Microsoft Outlook with Google Calendar, and Android phone. Synchronize Microsoft Outlook between multiple PCs using an external USB device, shared network folder of FTP. Share Outlook Calendar with Google Calendars. Sync Outlook Calendar, Contacts and Tasks folders. Includes improved product installation process and first start user experience. The update comes with improved performance of the software. Try the new Sync2 2.86 version now.|
|AkrutoSync||Use AkrutoSync to synchronize your Outlook Contacts, Calendar, Tasks and Notes directly with any Android, iOS (iPhone or iPad) or Windows Phone devices. AkrutoSync runs on your computer, not in the cloud. The program works with the phone's built-in apps, so there are no additional apps to install on the phone. After the initial set-up, the program syncs automatically. It works over Wi-Fi or the Internet. Akruto syncs Outlook with unlimited number of phones and tablets even if they are different brands and operating systems. Synchronization history feature lets you restore data if you change or delete something inadvertently.|
|Calendar Sync for Outlook and Google Calendar||Software to sync Outlook Calendar appointments with Google Calendar events. Allows you to sync one-way with either Outlook or Google as master as well as 2way sync by last changed appointments/events. Option to schedule a sync at regular intervals.|
|CompanionLink for Mac||CompanionLink for Mac keeps Outlook for Mac contacts, calendars, tasks, and categories synchronized with either a Google account, smartphone, or tablet. You can choose your destination in the Settings menu of the software. Two-way direct sync.|
|Contacts Sync for Outlook and Google Contacts||Contacts Sync - Synchronize Outlook Contacts with Gmail - Freeware and Pro version. 2way contacts sync, sync Outlook Categories, pictures, notes, sync by last changed contact, skip Outlook Category, sync Outlook Contacts to 2 Gmail accounts, Preview Sync with option to download entire Outlook/Gmail contact list as single CSV file and more.|
|EVO Collaborator for Outlook||EVO Collaborator for Outlook is a CardDAV and CalDAV add-in supporting 32- and 64-bit Outlook 2007 to 2013. Sync Outlook address books with CardDAV servers and calendars and tasks with CalDAV servers. Works with SabreDAV-based WebDAV servers, iCloud and Yahoo and AOL (in read only mode). Map Outlook's default address book, calendar or task within a CardDAV/CalDAV profile. Download EVO Collaborator for Outlook|
|GO Contact Sync Mod||GO Contact Sync Mod synchronizes your Microsoft Outlook contacts with your Google Mail address book, including pictures, categories and notes. Since version 3.5.6 it also syncs your Outlook Notes on demand to Google Drive. Since version 3.7.0 it also syncs your Outlook Calendar Appointments on demand to Google Calendar. This Mod fork adds many enhancements and bug fixes to the obviously dead project 'Go Contact Sync'.|
|gSyncit||gSyncit is an Outlook add-in that allows for two-way synchronization between Outlook calendars, contacts, notes, and tasks with your Google, iCloud, AOL, Fruxx, Yahoo, Memotoo and many other "DAV" enabled services. Also includes support for syncing attachments for calendar events. Works with Microsoft Outlook 2007, 2010, 2013, 2016, 2019, 2021 or Office 365 (Desktop Client) on Windows 7 and newer.|
|OggSync||Sync Google calendars and contacts with Outlook. Requires yearly subscription.|
|Outlook CalDav Synchronizer||Outlook CalDav Synchronizer is a free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google, SOGo, Nextcloud or any other CalDAV or CardDAV server. Supported Outlook versions are Office 365, 2019, 2016, 2013, 2010 and 2007.|
|Outlook Google Calendar Sync||Outlook Google Calendar Sync is completely free and syncs between any Outlook calendar and a Google calendar of your choice - either in a single direction or two-way. Attendees, reminders, free/busy attributes are all synced, events can be merged with existing if necessary, and even words in calendar subject's can be obfuscated if you have security concerns. Syncs can be configured on an automatic schedule, or simply upon request. It does not need to be installed (can just be unzipped) and works behind web proxies. Supports Outlook 2003 right through to Outlook 2016 64-bit!|
|Outlook4Gmail||Outlook4Gmail is a free Outlook add-in providing easy contacts synchronization of your Outlook and Gmail accounts and address books.This add-in uses these Outlook and Gmail contact details: Name, Company, Phones, Emails, Addresses, Dates, Persons, Notes, etc. You define the direction of synchronization/update: you can sync or update either the Outlook or the Gmail address book (one-way synchronization) or choose to update both accounts simultaneously (two-way synchronization). Paid version syncs Gmail calendar too.|
|Topalt Sync for Google and iCloud||Automatically synchronize your Outlook calendar and contacts with Google or iCloud. Access Outlook calendar and contacts on your Android phone or iPhone/iPad.|
You can create a Gmail account using your email address, then sync your Outlook calendar with the Gmail calendar and Android devices.
Additional articles on using Gmail with Outlook