How to Find and Merge Duplicate Contacts in HubSpot

I'm the solo builder behind DataClean, a duplicate-detection app for HubSpot — but this guide covers HubSpot's own native tools first, in full, because most people searching for this don't need a third-party app yet. Start here.

Using HubSpot's Manage Duplicates tool

Go to Contacts (or Companies, which has the same tool).
Click Actions in the top toolbar, then Manage Duplicates.
HubSpot shows pairs of records it's automatically flagged as likely duplicates, based on matching email addresses or phone numbers.
Review each pair — HubSpot shows the properties that differ between them — and either merge, or dismiss it if the two records genuinely aren't the same person.
You can also select multiple suggested pairs and merge or dismiss them in bulk rather than one at a time.

This tool is free on every HubSpot plan and it's the right first stop for most portals. Its one real constraint: it only surfaces pairs that already share an identical email or phone number.

Merging two specific records manually

If you've spotted a duplicate yourself that Manage Duplicates hasn't flagged — say, "Jon Smith" and "John Smith" under two different emails — you can merge them directly:

Open the contact record you want to keep as the primary.
Click the options menu (the "..." or gear icon, depending on your HubSpot UI version) near the top of the record.
Select Merge.
Search for and select the duplicate record to merge into this one.
HubSpot shows a preview of which properties will change before you confirm.

What a merge actually does to your data

It's worth understanding this before you merge anything, since it can't be undone from HubSpot's UI once confirmed:

Property values generally merge with the most recently updated non-empty value winning per property, with the primary record's value used as the tiebreaker.
Timeline and activity history — emails, calls, meetings, form submissions, website visits — combine onto the surviving record from both contacts.
Associations — deals, companies, tickets, tasks — carry over from the merged-away record onto the survivor.
The merged-away record's ID disappears. Anything outside HubSpot referencing that record ID by itself (a report, an external system, an old link) will break.

Because it's irreversible, a preview step that shows exactly what will change before you commit is worth having — whether that's HubSpot's own preview screen or a third-party tool's side-by-side diff.

Where the native tool stops helping

Manage Duplicates is genuinely good at what it does, and the two records it flags are almost always really the same person. What it can't do is anything requiring a judgment call about similarity rather than an exact string match — which is most of what makes duplicate cleanup tedious in the first place. If you're dealing with a backlog you suspect goes well beyond exact matches, especially after a messy CSV import, a fuzzy and phonetic matching tool like DataClean is built specifically for that gap — free to try up to 1,000 contacts, with the same kind of before-you-merge preview described above.

Frequently asked questions

How do I merge duplicate contacts in HubSpot?

Go to Contacts, select Actions, then Manage Duplicates to review HubSpot's automatically detected exact matches. For a specific pair it hasn't flagged, open one of the records, click the options menu, choose Merge, and select the other contact to merge into it.

What happens to data when you merge two contacts in HubSpot?

The record you merge into becomes the surviving contact. HubSpot combines property values (generally preferring the most recently updated non-empty value per property, with the primary record's values winning ties), and merges timelines, associations, and engagement history from both records onto the survivor. The merge cannot be undone from within HubSpot's UI.

Can HubSpot merge duplicates automatically?

HubSpot's Manage Duplicates tool lets you accept suggested exact matches in bulk, which is close to automatic but still requires a manual review step. Third-party tools can automate merging further based on confidence scoring, though most, including DataClean, still hold ambiguous matches for manual review rather than auto-merging blind.

Why doesn't HubSpot's Manage Duplicates tool show all my duplicates?

It only surfaces contacts with an identical email address or phone number. Duplicates under different emails, with typo'd names, or created through a messy CSV import won't appear there and need a fuzzy or phonetic matching tool, or a manual search, to find.

Written by Ryttle, solo builder of DataClean at Ryttle LLC. Merge behavior you've seen differ from this? Email me and I'll update it.