How to match existing HubSpot contacts when importing Excel data without creating duplicates

HubSpotHubSpot’sThe key to avoiding duplicate contacts when importing Excel data is validating your data against existingrecords before you import, not after. Most duplicate issues happen becausenative Excel import relies on basic email matching with limited error handling.

Here’s how to create a foolproof contact matching system that prevents duplicates and ensures your Excel data updates the right records every time.

Validate contact matches before importing using Coefficient

Coefficientsolves the duplicate contact problem by letting you cross-reference your Excel data against existing HubSpot contacts in a spreadsheet environment. This means you can identify and fix matching issues before any data touches HubSpot.

How to make it work

Step 1. Import your existing HubSpot contacts into Google Sheets.

Use Coefficient to pull all your HubSpot contacts with their Contact IDs and email addresses. This creates a reference dataset you can use to validate your Excel data. Make sure to include any custom properties you’ll be updating.

Step 2. Upload your Excel data to Google Sheets and clean the email addresses.

Copy your Excel data into a new tab. Use formulas like =TRIM(LOWER(A2)) to standardize email formatting – remove extra spaces, convert to lowercase, and fix any obvious formatting issues that could prevent matching.

Step 3. Create a contact matching validation column.

Use VLOOKUP or INDEX/MATCH to cross-reference your Excel emails against the HubSpot contact list: =VLOOKUP(B2,HubSpot_Contacts!B:C,2,FALSE). This will return the Contact ID if a match exists, or an error if it’s a new contact.

Step 4. Separate UPDATE and INSERT operations.

Create two datasets – one for existing contacts (where VLOOKUP found matches) and one for new contacts (where VLOOKUP returned errors). This lets you handle updates and new contact creation as separate, targeted operations.

Step 5. Execute the contact updates using Coefficient’s export features.

For existing contacts, use UPDATE operations that target specific Contact IDs. For new contacts, use INSERT operations. This eliminates the guesswork that causes HubSpot’s native import to create duplicates when email matching fails.

Stop playing duplicate contact cleanup

Try CoefficientThis validation approach prevents the manual cleanup work that typically follows failed HubSpot imports. By handling contact matching in spreadsheets first, you get reliable results every time.to streamline your contact import process.