Quick And Easy Duplicate Removal Using GCalToolkit:

Install and run GCalToolkit, then click "Save" to delete all the duplicates that were detected - for calendars of up to 500 events, that's all! The free trial of GCalToolkit will process up to 500 events - for more advanced calendar operations and to remove all duplicates from a larger calendar please purchase a subscription.

For serious duplication problems and advanced calendar repair/editing on calendars containing more than 500 events please download the GCalToolkit App from the "Downloads" page. Follow the detailed instructions to install, and take a look at the videos to ensure that you get the very best results. The Google Quota can cause frustration, which in turn causes nasty calendar accidents... so please read the instructions carefully, make backups when advised, and take things slowly but surely. If you get into trouble, please don't hesitate to get in touch.

Before you start please ensure that you really do have duplicates in Google Calendar, and not simply the same calendar displayed twice as can be the case on iPhone or Android devices if not set up correctly. If you can see duplicates in Google Calendar when viewed in a browser then you have a duplication problem and should follow the steps listed after the video:


STEP 1: Make an iCal backup THEN remove the cause of the duplication 

  • EXPORT your Google Calendars as a zipped iCal file (*.ics)
  • Disable all syncing with this Google Calendar account AND/OR Change Google password temporarily
  • Disable sharing for all affected calendars

If you are unable to EXPORT (in SETTINGS > CALENDARS TAB > EXPORT BUTTON) then you have reached the Google Calendar Quota for activity in this account:

If this is the case, you can probably still use the calendar normally in a browser, but anything related to multiple events such as Export, Calendar Delete, Syncing and GCalToolkit itself will not work as usual... Google usually reset quota after 24 hours, but if you had a massive number of duplicates then you may have triggered other quota limits. The most I have seen is 9 days waiting for normal access to return... but this is VERY rare.

As soon as the quota is reset for your account, finish the BACKUP - complete with duplicates. 

STEP 2: Wipe synced devices, remove Google Calendar duplicates 

  • Wipe any synced devices in the Calendar Settings for your device (and any third party software). If for some reason Google Calendar contains an incomplete copy of your calendar data, you may want to back this data up first to try and merge it with the clean Google Calendar.
  • Remove all the duplicates in Google Calendar with GCalToolkit (click below to download the correct version for your computer). 

Once you have downloaded one or several calendars with GCalToolkit you will see a list of all your events (by default repeats will display only once for the very first occurence - see "Download Repeats as Single Events" below if you need to see every repeat in a series). Duplicates will be colored RED, and the "Duplicates" total top right tells you how many are to be deleted. Click "Save" to delete all the duplicates from Google Calendar. This may take some time - leave the program open and make sure that you are not disconnected from the internet during this process for best results.

The deleted duplicate events will eventually all be marked "Deleted" in green. Events are only marked as "Deleted" when Google Calendar confirms that an event has in fact been deleted, so if these events still display in the browser be sure to refresh the page, and maybe even wait an hour or so if you have made thousands of modifications to Google Calendar. 

STEP 3: Backup your clean Google Calendar & enable syncing one device at a time. 

First backup as an iCal file as you did in STEP 1, then either enable syncing on each device (or change your Google Password back to the original before you began). If you are not sure which device caused the problem (probably Outlook or BlackBerry) then try enabling your devices one by one, monitoring closely in case the duplicates start to be recreated; if they are, immediately disable sync (or change Google Password again), wipe the device, and check for outdated or buggy sync software, or timezone/date/time errors on your device and Google Calendar.


If all duplicates are not detected (they should be marked red, and the total displayed top right next to "Duplicate Events") then first try the "Relax Duplicates" option in the "Options" menu. This allows events with the same Start Time and Title to be flagged as duplicates even if the description or location are different. The OS X and JAVA versions allow complete control over duplicate detection rules.

Sometimes single events will duplicate a repeat event, most commonly with Outlook sync problems - in these cases you will need to check the checkbox called "Download Repeats as Single Events". Once downloaded, GCalToolkit will mark as duplicates the singles that duplicate the repeat event. When deleting duplicates across several calendars you can also set a "preferred calendar" in the "Options" to choose which calendar takes priority when duplicates are found in different calendars.


44,269 duplicates! Dubious honor of most dupes ever! I won't get into how I got so many duplicates, but without this product I'd be manually deleting until I died. When I found some internet mentions of this software I initially thought it sounded too good to be true, but the price was so low I had to try it. After initially trying the free demo (500 deletes) I saw the potential and bought it. Probably due to the sheer size of my problem I had a little difficulty loading my calendar so emailed the developer. Within a few minutes I received his first response "You now hold the absolute record for the largest number of duplicates I have ever seen... "...lol....dubious honor indeed. Neil promptly answered the few questions I had, made some suggestions, and even OFFERED TO DO IT FOR ME. CAN YOU SAY CUSTOMER SERVICE? Still, wanting to attempt myself I ran the software yesterday and last night and this morning, VOILA, no dupes....NONE!


Simply put, this product works and saved me hundreds of hours. Can't say enough about it or Neil

"This software works, PERIOD!" (robmurray63)

It was amazing, I had 30,000 duplicate entries ad they were gone in one hour with one click! The team helped me with some questions and before I knew it, I was back up and running with zero duplicates in my calendar.


Here's the deal. If you need duplicates removed from your calendar or if you are getting duplicates between your BlackBerry, Outlook and Google Calendars, then this is the software you need.

It is a no nonsense platform that gets the job done. Any time spent looking at products that do the same as this software afterwards is a waste of time.


In addition to being probably the best Google Calendar Duplicate Removal Tool, GCalToolkit membership comes with personal support from an official Google Calendar Product Expert, permanent free updates during the membership period, access to desktop software for macOS/Linux/Windows, and custom modifications (where possible) at no extra charge. If you need a special button whose sole purpose in life is to move non-repeating events with no specified location that fall on specific days into a secondary calendar... I'll add it for you!

GCalToolkit has many uses in addition to deleting duplicates:

  • Repair calendar sync problems and undo iCal import
  • Delete multiple calendar events based on date, type or content
  • Edit multiple events in Google Calendar
  • Force Android Calendar to sync ALL past events by adding a prefix or suffix
  • Bulk edit event reminders, busy/free, privacy etc.
  • Export customized agenda event lists as CSV for printing or spreadsheets
  • Multiple Copy/Move events between calendars
  • Safe and Secure: uses OAuth 2.0 and the latest Google Calendar API
  • Personal support from an official Google Calendar Product Expert
  • 100% Satisfaction - Money Back Guarantee!