How to Format CSV for Outlook: Email List Import Guide

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Why Outlook CSV Imports Fail

Microsoft Outlook is notoriously strict when it comes to importing CSV files. A single incorrect delimiter, a missing header row, or the wrong character encoding will cause the import to fail silently – contacts are either not imported at all, or fields end up in the wrong columns.

The most common reasons for failed imports include:

• Wrong delimiter: Depending on your regional settings, Outlook expects either a comma or a semicolon as the column separator.
• Missing or incorrect headers: Outlook requires specific English column names to map fields correctly.
• Encoding issues: Special characters (umlauts, accents, Asian characters) appear garbled because the file is not saved with the correct encoding.
• Extra whitespace or line breaks: Hidden characters in cells can break the import parser.

Step 1: The Required CSV Structure

Outlook requires specific column names in the header row. Our tool handles this automatically when you select the “Outlook” export mode. If you are building the CSV manually, the first row must contain at least these headers:

Minimum required headers for Outlook

First Name,Last Name,E-mail Address

Outlook supports many additional fields. Here are the most commonly used ones:

Extended headers for a complete contact import

First Name,Last Name,E-mail Address,Company,Job Title,Business Phone,Mobile Phone

Important: The column names must match Outlook’s expected field names exactly. “Email” or “email_address” will not be recognized – it must be E-mail Address (with the hyphen and capital letters).

Example CSV Content

A valid Outlook-compatible CSV file

First Name,Last Name,E-mail Address,Company
John,Smith,john.smith@example.com,Acme Corp
Jane,Doe,jane.doe@example.com,Tech Solutions
Max,Mueller,max.mueller@example.com,Digital Agency

Step 2: Delimiters and Encoding

Regional Delimiter Differences

This is one of the most common pitfalls. The CSV delimiter depends on your Windows regional settings:

• English-speaking countries (US, UK, AU): Outlook expects the comma (,) as delimiter.
• Most European countries (DE, FR, ES, IT): Outlook expects the semicolon (;) because the comma is used as the decimal separator in these locales.

If you are unsure which delimiter your Outlook installation expects, check your Windows settings under Control Panel → Region → Additional Settings → List Separator.

Character Encoding: UTF-8 with BOM

To ensure special characters (umlauts, accents, Cyrillic, CJK characters) display correctly, the file must be saved as UTF-8 with BOM (Byte Order Mark). The BOM is an invisible marker at the beginning of the file that tells Outlook to interpret the content as UTF-8.

Without the BOM, Outlook defaults to the system’s ANSI encoding, which causes characters like ä, ö, ü, é, or ñ to display as garbled text.

Save as UTF-8 with BOM in Python

import csv

contacts = [
    ["John", "Smith", "john@example.com"],
    ["Müller", "Hans", "hans@example.com"],
]

with open("outlook_contacts.csv", "w", encoding="utf-8-sig", newline="") as f:
    writer = csv.writer(f)
    writer.writerow(["First Name", "Last Name", "E-mail Address"])
    writer.writerows(contacts)

The utf-8-sig encoding in Python automatically adds the BOM to the file.

Step 3: The Import Process in Outlook

1. Open Outlook and go to File → Open & Export → Import/Export.
2. Select “Import from another program or file” and click Next.
3. Choose “Comma Separated Values” and click Next.
4. Browse to your CSV file and select how to handle duplicates (replace, allow, or skip).
5. Select the destination folder (usually Contacts).
6. Critical step: Click “Map Custom Fields…” to verify that your CSV columns are correctly linked to Outlook’s contact fields. Drag fields from the left (your CSV) to the right (Outlook fields) to correct any mismatches.
7. Click Finish to start the import.

Using Our Tool for Automatic Formatting

The easiest way to create an Outlook-compatible CSV is to use extract-emails.com:

1. Paste your text, upload a file, or enter a URL to extract email addresses.
2. Once the extraction is complete, click the Download button.
3. Select “Outlook CSV” as the export format.
4. The tool automatically generates a properly formatted CSV with the correct headers, UTF-8 BOM encoding, and the appropriate delimiter for your region.

Troubleshooting Common Problems

All data appears in a single column

This happens when the delimiter does not match your regional settings. If your CSV uses commas but Outlook expects semicolons (or vice versa), all data will be crammed into the first column. Solution: Open the CSV in a text editor and replace all commas with semicolons (or the reverse).

Special characters are garbled

The file is not saved as UTF-8 with BOM. Open it in a text editor like Notepad++ or VS Code, change the encoding to “UTF-8 with BOM”, and save again.

Email addresses end up in the wrong field

The header row does not use Outlook’s expected column names. Make sure the email column is labeled exactly E-mail Address, not “Email”, “email”, or “Mail”. Always use the “Map Custom Fields” dialog to verify the mapping before finishing the import.

Outlook imports zero contacts

This usually means the CSV file is empty, has no valid header row, or uses an encoding that Outlook cannot read. Verify the file is not empty and re-save it with proper encoding.

Pro Tips for Large Email Lists

• Split large files: Outlook can struggle with CSV files containing more than 10,000 contacts. Split them into smaller batches for reliable imports.
• Remove duplicates first: Use our extractor’s built-in deduplication to clean the list before creating the CSV.
• Test with a small sample: Before importing thousands of contacts, test with 5–10 rows to verify the formatting is correct.
• Back up your contacts: Always export your existing contacts before importing new ones, so you can restore them if something goes wrong.
• Use domain filtering: If you only need contacts from specific companies, use our domain filter to create a targeted list before export.

Importing Contacts in Outlook on the Web (Microsoft 365)

The classic desktop Outlook import wizard described above applies to the installed Windows app. If you use Outlook on the Web (outlook.office.com or outlook.live.com), the process is different:

1. Open outlook.live.com/people or navigate to People in Outlook 365.
2. Click Manage → Import contacts in the top toolbar.
3. Choose Google CSV or Outlook CSV format depending on your source file.
4. Select your file and click Import. The web version handles most UTF-8 CSV files without the BOM requirement that the desktop app needs.

Note: The web importer has a limit of 1,000 contacts per file. For larger lists, split the CSV into batches of 999 rows (plus the header) and import each batch separately.

Migrating from Google Contacts or Gmail

If your email list originated in Gmail or Google Workspace, you can export it in a format that Outlook understands directly:

1. Go to contacts.google.com and select the contacts you want to move.
2. Click Export and choose Outlook CSV format. Google generates a CSV that maps directly to Outlook’s column headers.
3. Import the file into Outlook using either the desktop wizard or the web importer described above.

If your source is a plain list of email addresses (extracted from documents, spreadsheets, or inboxes), you first need to build a valid CSV. Our extractor lets you copy extracted emails and download them as a formatted CSV ready for Outlook import in one click.

Columns that Outlook recognises from Google’s export: First Name, Last Name, E-mail Address, Company, Phone 1 - Value. Columns with other names are silently ignored unless you remap them manually in the “Map Custom Fields” step.

Frequently Asked Questions

Can I import to Outlook on a Mac?

Yes. In Outlook for Mac, go to File → Import, choose Contacts or messages from a text file, and select your CSV. The column mapping dialog works the same as on Windows.

Why do some contacts import without an email address?

The most common cause is a column name mismatch. Outlook requires the header to be exactly E-mail Address (with a hyphen). Use the “Map Custom Fields” dialog to drag the source column to the correct Outlook field before finishing the import.

Is there a limit to how many contacts I can import at once?

The desktop Outlook app has no hard documented limit, but performance degrades above 10,000 rows. Outlook on the Web caps imports at 1,000 contacts per file. For large lists, import in batches.

How do I avoid creating duplicate contacts?

Outlook’s importer will warn you about duplicates (matching email address or name) and give you the option to merge or skip. For large imports, it’s faster to deduplicate your CSV before importing using our free email list cleaner.