---
title: How to Clean Up Duplicate Contacts Before Importing Into a CRM
description: A step-by-step checklist for removing duplicate contacts and fixing messy data in Google Sheets or Excel before you import it into any CRM.
---

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Published 14 October 2026

Data clean-up

# How to clean up duplicate contacts before importing into a CRM

7 min read · Garner Desk

Importing a messy list is the fastest way to make a new CRM useless. The same client shows up three times, half the names are in capitals, and nobody trusts the data, so nobody uses it.

Here's the clean-up checklist we run before every import. It works in Google Sheets or Excel, and you don't need to be a spreadsheet expert.

## Before you start: make a copy

Duplicate your file and work on the copy. If something goes wrong, you still have the original.

## Step 1: Get every contact into one sheet with the same columns

Combine your exports (inbox, LinkedIn, phone, old trackers) into one sheet. Line them up under the same headings: First name, Last name, Email, Company, Phone, Source, Notes. Delete columns you'll never use.

## Step 2: Standardise email addresses

The email address is how you'll spot duplicates, so it has to be consistent. In a new column, use:

> =LOWER(TRIM(C2))

This removes stray spaces and makes everything lower case, so *Sam@Example.com*  and *sam@example.com* are recognised as the same person. Copy the results and paste them back as values over the original column.

## Step 3: Flag the duplicates before deleting anything

Add a column called "Duplicate?" and use:

> =COUNTIF(C:C, C2)\>1

Anything showing TRUE appears more than once. Sort by email so duplicates sit next to each other. Now go through them and copy any useful notes into the row you'll keep. Usually that's the one with the most complete details.

## Step 4: Remove the duplicates

- **Google Sheets:** Data, then Data cleanup, then Remove duplicates. Choose the Email column only.
- **Excel:** Data, then Remove Duplicates. Again, tick only the Email column.

Checking only the Email column matters. If you check every column, two rows for the same person with slightly different notes won't count as duplicates.

## Step 5: Catch the sneaky ones

Some duplicates have different emails: someone who used a personal address once and a work address later. Sort by Last name, then Company, and scan for pairs. Keep the work email for business contacts and add the other to Notes.

## Step 6: Fix names

- To fix capitals, use **=PROPER(A2)**. It turns "SARAH JONES" into "Sarah Jones". Watch for names like McDonald or O'Brien, which may need a manual tweak.
- To split a full name, use **=SPLIT(A2, " ")** in Google Sheets, or Data, then Text to Columns in Excel.
- Fill in missing first names where you can. "Hi there" emails get fewer replies.

## Step 7: Remove the junk

Delete rows that will never become clients:

- no-reply and notification addresses
- newsletters and software tools
- your own suppliers, unless you also sell to them
- rows with no email and no phone number

Generic addresses like info@ can stay if they're the only way to reach a business you want to work with.

## Step 8: Add a Status column

Before importing, tag each contact: Hot, Warm, Past client or Cold. It takes a while, but it's the difference between a list and a pipeline. Our guide to [organising scattered leads](https://www.garnerdesk.com/articles/organise-scattered-leads?hsLang=en) explains each group.

## Final checklist before you import

- One row per person
- Emails in lower case, no spaces
- Names in normal capitals, split into first and last
- No junk addresses
- A Status for every contact
- A test import of 10 rows first

Then follow our guide to [setting up a free HubSpot CRM](https://www.garnerdesk.com/articles/set-up-free-hubspot-crm?hsLang=en), or import into whichever CRM you use.

### Rather hand this over?

This is exactly what our Gather package does: up to 500 contacts cleaned, de-duplicated and sorted, delivered as a file ready to import into any CRM. Done in 5 working days.

[Book a free 20-minute call](https://www.garnerdesk.com/#book)

[Garner Desk](https://www.garnerdesk.com/?hsLang=en)

[Pricing](https://www.garnerdesk.com/pricing?hsLang=en)[Articles](https://www.garnerdesk.com/articles?hsLang=en)[Privacy](https://www.garnerdesk.com/privacy?hsLang=en)[hello@garnerdesk.com](mailto:hello@garnerdesk.com)© 2026 Garner Desk

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