How to merge duplicate contacts across accounts

You met someone through your personal email. Now you want to write to them from your work account. They are not there. So you look them up in your personal account and copy the address across. Now you have 2 contacts for the same person.

That is not a mistake you made. It happens when your contacts live in more than one account. Here is how to merge them, and why your tools do not.

Why the same person ends up in more than one account

Google, Microsoft and Apple each keep their own address book. Google and Microsoft do not sync contacts with each other by default.

Google makes an add-in that syncs a Google Workspace account with Outlook on Windows. It does not join the same person in two accounts.

An iPhone can show contacts from iCloud, Microsoft Exchange and CardDAV accounts in one list. The same person can still appear twice.

After a few years, this is what two accounts can look like:

Six contacts, one person. Each is out of date in a different way. The phone numbers differ. Two have mobile numbers you changed months ago.

This costs you something every day:

• You are in the wrong mailbox. You met them through your personal address. Now you need to write from the business one, and they are not there.
• You do not know who is calling. A client saved in Microsoft 365 rings your phone. Your phone reads Google. All you see is a number.
• You updated it in one place. The other accounts keep the old number. You find out when the call does not connect.

None of this is urgent enough to fix properly. That is why it keeps happening.

Why you can't merge duplicate contacts across accounts in Google

Google's help page says: "You can't merge contacts that are saved in different Google Accounts." This is true for two accounts you own. It is also true for a personal account and a work account. You can read it in Google's steps for merging contacts.

Adding the other account to your phone shows its contacts in the same list. The same person can still appear twice.

Each service merges inside one account only. To clean up one account first, see how to remove duplicate contacts in Google, Outlook, iCloud or a CardDAV address book.

How to merge duplicate contacts across accounts

You have 3 options. They are not equally good.

• Pick one account as your address book. Save new contacts there and stop using the others. This is free and it works today. It also depends on you. Each time you save someone from the wrong mailbox, you have 2 contacts again.
• Copy contacts between 2 accounts with a sync add-in. Outlook CalDav Synchronizer syncs contacts between Outlook and Google, or between Outlook and a CardDAV server. It syncs both ways. It runs inside Outlook on Windows. Its feature list has no duplicate merge, so the same person can still appear twice.
• Use a tool that reads all your accounts. It finds the same person in more than one account and merges them into one contact. It sends the merged contact to your accounts. This option removes the duplicates.

Any tool that merges 2 accounts needs write access to both. Before you connect one, ask these questions.

What to ask before you let a tool merge your contacts

• Can I see the duplicates before anything merges? You should review each merge, or choose to turn on automatic merging yourself.
• Can I choose which value to keep? A person can have 3 phone numbers. Keeping all 3 is the right answer.
• Is there a backup before the first change? Ask whether the tool backs up each account before it writes to it.
• Can I undo a merge? You want to undo the merge itself, not only delete a contact. Ask how long you can undo it.
• Can I take my contacts out? You should be able to export them as vCard whenever you want.

How to merge duplicate contacts across accounts in ContactZapp

ContactZapp works with Google, Microsoft, Apple and CardDAV. It finds duplicates by name, email, phone and address, inside one account and across all your accounts. A merge keeps every phone number, email and address.

Here is how to merge one person saved in your Google and Microsoft 365 accounts.

1. 1

   Connect 2 accounts

   Sign in to ContactZapp and connect your Google account. Then connect your Microsoft 365 account. The free plan includes 2 accounts. A backup of each account is taken before ContactZapp first writes to it.

2. 2

   Open the duplicates

   Open Review duplicates. Each group is one person that ContactZapp found more than once, in one account or across your accounts.

3. 3

   Review a group that spans 2 accounts

   Open a group with a contact from each account. We show the contacts side by side and suggest the values to keep. Click any other value to keep it instead. If they are 2 different people, choose Don't merge. ContactZapp does not suggest those 2 again.

4. 4

   Merge

   Click Merge these 2. The 2 contacts become one contact.

5. 5

   Check the contact in both accounts

   The merged contact is sent to both accounts. Open it in ContactZapp to see every account it is in.

If a merge was wrong, undo it from History. You can undo any merge for 12 months.

Auto-Merge is off until you turn it on. When you trust the suggestions, turn it on and ContactZapp merges the duplicates for you. You can undo those merges too.

The short version

The same person is in more than one account because Google, Microsoft and Apple keep separate address books. Each one merges only inside one account. To merge duplicate contacts across accounts, you need a tool that reads all of them.

See what ContactZapp syncs and merges.

FAQ

Can Google merge contacts from different accounts? No. Google's help page says: "You can't merge contacts that are saved in different Google Accounts." Google merges only inside one Google account. ContactZapp finds the same person across your accounts, and you merge once.

How do I merge duplicate contacts across Gmail and Outlook? Connect both accounts to ContactZapp. It shows the duplicates it finds across them, side by side. You merge once and the merged contact is sent to both accounts.

Is it safe to connect my accounts to a merge tool? Any tool that merges 2 accounts needs write access to both. In ContactZapp, a backup of each account is taken before ContactZapp first writes to it. Auto-Merge is off until you turn it on. You can undo any merge for 12 months.

Does this work with the free plan? Yes. Connect 2 accounts of any size and see all your contacts and duplicates, with no time limit and no card. The free plan syncs 100 contacts between your accounts. Upgrade to sync the rest.