Duplicate contacts are one of the most common data quality problems in HubSpot. If your team imports lists from multiple sources, uses web forms, and captures leads through events or integrations, you will almost certainly end up with the same person appearing more than once in your CRM. HubSpot has built-in tools to find and merge these duplicates, and a clear process makes the job manageable.
Go to Contacts, then click Actions > Manage duplicates. HubSpot compares contacts by email address, first name, last name, and phone number, then groups suspected pairs for your review.
For each pair, HubSpot shows you the key properties side by side. You choose which record becomes the primary (the one that survives the merge) and which becomes the secondary (its data is merged in, then the secondary is deleted).
Click Merge to combine the two records. The primary contact inherits all activities, emails, deals, and timeline events from the secondary. Click Not a duplicate if HubSpot flagged two different people by mistake.
In Settings > Data Management > Duplicates, configure how HubSpot identifies matches. Adding phone number and company name to the match criteria reduces future duplicates from LINE or offline form sources.
How does HubSpot identify duplicate contacts?
HubSpot uses a similarity algorithm that compares several properties at once: email address (the strongest signal), first name, last name, phone number, and company name. Two records do not need to share the same email to be flagged as potential duplicates. A contact with no email address can still match another record if the name and phone number are close enough.
Admins with the necessary permissions can also configure which properties HubSpot weighs more heavily. If your CRM relies heavily on phone numbers for LINE-sourced contacts, raising the weight of phone number matching tends to surface more relevant pairs.
What happens to data when you merge contacts?
When you merge two contacts in HubSpot, the system combines their data following clear rules:
- Activities and timeline: emails, calls, notes, meetings, and form submissions from both records appear on the merged contact’s timeline.
- Property values: where both records have a value for the same property, you can choose which one to keep at the time of merge. HubSpot defaults to the primary contact’s value but gives you the option to switch.
- Associated records: deals, tickets, and company associations from both contacts move to the merged record.
- List memberships: the merged contact inherits static list memberships from both records. Active list memberships recalculate on the next list refresh.
Once merged, the secondary record is permanently deleted. There is no undo option in the native interface, so it is worth confirming the correct primary record before clicking Merge.
Can you merge contacts in bulk?
The native Duplicates Manager processes pairs one at a time. For portals with hundreds of duplicate pairs, this can be slow.
Two options speed this up:
- HubSpot Operations Hub Professional and above includes a data quality automation feature that can flag and, in some configurations, auto-merge obvious duplicates based on matching email addresses.
- Third-party deduplication tools such as Dedupely and Insycle connect to your HubSpot portal via API and can bulk-merge large sets of duplicates based on rules you define. These tools are useful for one-off cleanup projects after a major import.
For ongoing prevention, the more effective approach is fixing the data sources that create duplicates in the first place.
How do you prevent duplicates from appearing in the first place?
Deduplication is easier to prevent than to fix. Common sources of duplicates in Southeast Asian HubSpot portals include:
- Form submissions where contacts use different email addresses (personal vs work).
- LINE OA integrations that create a new contact using a LINE user ID without matching against an existing email address.
- CSV imports from sales teams who do not check the existing database first.
- Event or exhibition registrations imported from a separate system.
The strongest prevention measures are:
- Email as the required identifier on every form. No email, no form submission. This is the single field HubSpot can always match against reliably.
- Deduplication checks before every import. Export your existing contacts’ emails to a spreadsheet, then VLOOKUP against your import file before uploading. Remove matches before importing.
- Consistent use of the HubSpot email tracking domain. Contacts who click tracked emails get matched to existing records rather than creating new ones.
- Integration mapping review. When connecting a new tool (LINE, WhatsApp, event platform), confirm how the integration matches incoming contacts to existing HubSpot records. The default behaviour varies by connector.
What permissions do you need to merge contacts in HubSpot?
To use the Duplicates Manager and merge contacts, you need at least the Bulk delete objects permission in your HubSpot account. Super admins have this by default. If a team member cannot see the Manage duplicates option under Actions, their role likely does not include this permission. Super admins can grant it under Settings > Users & Teams.
For portals where data integrity is critical, it is worth restricting merge access to one or two designated users rather than allowing all sales reps to merge contacts independently.
How does contact deduplication relate to HubSpot data quality tools?
The Duplicates Manager is one part of HubSpot’s broader data quality suite. Operations Hub Professional and Enterprise add:
- Data quality automation: workflows that automatically fix common data issues like formatting inconsistencies in phone numbers or country fields.
- Property history: a log of every change to a contact’s properties, useful for understanding how a duplicate arose.
- Data quality command centre: a dashboard that surfaces data health metrics across your portal, including duplicate counts, missing property rates, and formatting errors.
For teams running HubSpot at scale across Southeast Asia, particularly those managing contacts from multiple countries and language settings, these tools reduce the manual overhead of keeping contact data clean.
Frequently asked questions
Can I unmerge contacts after merging?
No. Once two contacts are merged in HubSpot, the secondary record is permanently deleted and cannot be restored through the native interface. Some third-party backup tools can snapshot your contact database before a bulk merge, which provides a recovery path if something goes wrong. For large cleanup projects, a full export of your contact database before merging is a practical precaution.
Does merging affect contact ownership?
The merged contact keeps the contact owner assigned to the primary record. If you want the merged contact to be owned by someone else, update the Contact owner property after merging.
How often should I run the Duplicates Manager?
A monthly review is a practical minimum for most portals. Portals that run regular imports from external sources (trade shows, webinars, offline registrations) benefit from a review after each import event rather than waiting for a monthly cycle.
What about duplicate companies?
HubSpot also has a Duplicates Manager for companies, accessible via the Companies view under Actions > Manage duplicates. The same merge logic applies: choose a primary, review properties, and merge. Company duplicates often appear when the same business is added by different sales reps using slightly different name formats.
An independent informational resource produced by a HubSpot Platinum Partner. HubSpot is a trademark of HubSpot, Inc.
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