Migrating contacts from Excel to a CRM: clean and without data loss

Migrating contacts from Excel to a CRM works cleanly when you follow five steps: tidy the spreadsheet, map each column to a CRM field, export to CSV, import a small test batch first, then the rest. That's how you avoid duplicates and data loss. With Advanzo you import your contacts in minutes – a lean Swiss CRM with Swiss hosting and a free entry point.

Updated: July 2026

The move is worth it, and the numbers show why. Around half of Switzerland's nearly 600,000 active SMEs still run without a dedicated CRM, keeping customer data in Excel, Outlook and notes (Swiss SME Portal / SECO, kmu.admin.ch, 2025). The real problem is data quality: B2B contact data decays by roughly 22–30% a year as addresses, phone numbers and roles keep changing (Cleanlist, 2026). An unmaintained spreadsheet therefore loses almost a third of its value every year – a structured CRM with required fields and clear ownership slows that decay.

How do I migrate contacts from Excel to a CRM?

In five steps: clean the Excel file, give the columns clear headers, export as CSV (UTF-8), map each column to a CRM field, and import 10–20 test rows first. If the result looks right, the rest follows. With a tidy list the whole job usually takes under an hour.

1. Clean: remove duplicates, delete empty rows, one contact per row.
2. Structure: split first and last name, use unambiguous column titles (email, phone, company).
3. Export: save as CSV with UTF-8 encoding so special characters survive.
4. Map: assign every column to the matching CRM field during import.
5. Test and import: check a small batch first, then bring in the rest.

How do I prepare my Excel list for import?

Preparation decides the outcome. Use a header row with clear titles, exactly one contact per row, and separate columns for first name, last name, company, email and phone. Remove colour highlights and comments – they're ignored on import anyway.

Common traps in spreadsheets that have grown over the years:

• Several people in one cell: "Muster AG (Anna & Beat)" belongs on two rows.
• Mixed formats: phone numbers sometimes with, sometimes without a country code. Standardise to +41.
• Merged cells: they break the CSV export – unmerge them first.
• Duplicate contacts: clean up via "Data → Remove duplicates", ideally keyed on the email address.

Which Excel columns go into which CRM field?

Clean mapping stops information from landing in the wrong field or getting lost. Assign every Excel column to a CRM field deliberately; whatever doesn't fit comes across as a note. The table below shows a typical mapping for an SME.

How do I avoid duplicates and data loss?

Data loss rarely happens during the import itself; it comes from poor preparation and missing checks. Three ground rules protect you: a unique key (usually the email address), a saved copy of the original file, and a test import before the full run.

• Save the original: keep an untouched copy of the Excel file before you delete anything.
• Unique key: using the email address as the duplicate criterion prevents double contacts.
• Test import: check on 10–20 rows that special characters, phone formats and mapping are right.
• Verify after import: compare a sample of five contacts against the original.

A worked example from a Swiss SME

A trades business with around 900 contacts kept its customer list in Excel for years – maintained by one person, with duplicates and inconsistent phone numbers. Before migrating, the team cleaned the list in an hour: duplicates removed by email, names split, numbers standardised to +41.

Then a test import of 15 rows, a check, then the rest. The result: instead of 900, some 840 clean contacts were imported – the 60 duplicates fell away and not a single real contact was lost. Since the contacts moved into the CRM, the whole team sees the same state and nobody digs through old spreadsheets. The biggest win wasn't the import but the discipline afterwards: every new contact is captured straight away, instead of ending up in yet another Excel file.

Migration checklist

This checklist takes you safely through the move – from preparation to the post-import check:

• Original file saved as a copy
• One row per contact, no empty rows
• First and last name separated, clear column titles
• Phone numbers standardised to +41
• Duplicates removed by email
• Exported as CSV (UTF-8)
• Field mapping defined, a note field for the rest
• Test import of 10–20 rows checked
• Sample verified after import

What happens after the migration?

The import is the start, not the finish. To keep the data clean you need a simple routine: capture new contacts in the CRM straight away, define required fields, and check for obvious duplicates once a quarter. That stops a parallel Excel list from creeping back in.

For more, see our guide to CRM pricing models, the comparison CRM vs Excel and the overview of lead management for SMEs. If you want to bring contacts across from other tools, you'll find the right routes on our integrations page.

Frequently asked questions (FAQ)

How do I migrate contacts from Excel to a CRM?

Clean the Excel list, give the columns clear headers, export it as CSV (UTF-8), map each column to a CRM field during import, and check a small test batch first. Then import the rest and verify for duplicates – with a tidy list, in under an hour.

How do I avoid duplicates on import?

Use the email address as a unique key and remove duplicates in Excel first via "Data → Remove duplicates". A good CRM also recognises existing contacts by email on import and won't create them twice.

Which file format do I need for the import?

A CSV file with UTF-8 encoding. UTF-8 ensures accented characters such as ä, ö, ü come across correctly. In Excel, use "Save As" and choose the "CSV UTF-8" format.

Will I lose data during the migration?

Not if you're prepared. Save the original file, run a test import and verify a sample afterwards. Fields with no counterpart in the CRM come across as a note rather than being dropped.

How long does the migration take?

With a tidy list, under an hour. Almost all the effort is in preparation – the import itself takes only minutes. Large or messy lists need correspondingly longer to clean up.

Can I merge contacts from several Excel files?

Yes. Combine the files into one list in Excel first, standardise the columns, then remove duplicates by email. Import that single cleaned file – it's safer than several separate imports.

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