Format Guidelines for Your Import File

Before you import a file of contacts to MailChimp, review the format of each column in your file. During the import process, you'll match each column in your file to a column in your MailChimp list, which we call a list field. Certain list fields, like email address or birthday, require a specific format in your import file.

In this article, you'll learn how to format each column in your file to get the best results when you import.

Before You Start

  • The only field that MailChimp requires is Email Address. Any other fields you want to include are useful for personalizing campaigns, but optional.
  • You can arrange the columns in your file in any order.
  • Clearly label each column in your import file so you can easily choose the field type during the import process. For example, if you have a column named "Contact Email Addresses," you'll know to choose the email address field type.
  • If you've already started an import, learn how to review and edit your list fields or troubleshoot your import.

Required Field

Email Address

Your import file must include a column for email address, and can provide only one email for each subscriber.

Before you import, doublecheck this column to make sure that extra spaces don't appear before or after your email addresses. If your subscriber email addresses contain international symbols like ñ or é, keep in mind that we can only support addresses with international characters after the @ symbol. 

Optional Basic Fields

Use these common list field types to quickly add extra information to your subscriber list.


Text fields are limited to a maximum of 255 bytes of information, and will be clipped if there's too much. In many alphabets, this is equal to 255 characters. Some alphabets or symbolic characters, like emoji, use more than one byte of information per character, so it isn't always a one-to-one ratio.

Use text fields for:

  • first name and last name
  • subscriber language preferences
  • international postal codes
  • website URLs for campaign links
  • numbers without comma separators
  • additional data you want to add to your list, like job title or company name


This field is included when you create a list, but is hidden from signup forms unless you choose to make it visible. Mailing addresses that use this field must appear in a single cell and should include the country. If the address information in your list import is stored in multiple columns, combine your address fields before you import, or set up individual text fields to import your data.

To format an address cell, separate each line of the address with two spaces, as shown in this example.

1701 Bristol Ave.  Barrington   Rhode Island   02806  USA

Example of formatted address cell.


This field is included when you create a new list, but is hidden from signup forms unless you choose to make it visible. It uses international format by default. If you know you’ll only have U.S. phone numbers, choose the (###) ###-#### format.

Zip Code

Zip code fields can only contain five digits:


Use the Zip code field in combination with a text field(s) if you have U.S. address data stored in separate columns, and you don’t want to combine them. To store international postal codes, use an additional text field.

If you want to store address data in a single column, use our Address field type.


Use a number field to import numbers or currency values to your list. We'll add comma separators to large numbers like 1,000 or 1,000,000.


To import dates other than birthdays, use either of these two formats.

YYYY-MM-DD (ISO Standard)

In the examples, MM is month, DD is day, and YYYY is a four-digit year. MailChimp will attempt to convert the date field to match your account's default date format. For best results, we recommend that you use the ISO standard format, YYYY-MM-DD.

Additional Optional Fields

Use these additional field types to add more complex information to your list. Formatting these field types can be tricky, so be sure your import file's columns match the exact format of these examples.


To send an automatic birthday or annually recurring message to your subscribers, use a birthday field instead of a regular date field. Be sure to use the format, Month/Day.


birthday format list


Image fields in your import file must contain the full source URL for a hosted image, which can be used to insert custom, dynamic images in campaigns.


Website fields can be used to store custom links for each subscriber. Use merge tags to insert these custom links into your campaign. To display the custom URL in your campaign, use a website field. If you want to hyperlink the custom URL to descriptive text or an image in your campaign, use a text field instead. Website fields must include the full URL of a website, including http://.

website example


If you plan to use groups in your list, you can add subscribers to groups during the import process. The group column must be formatted as shown in the example or you may encounter errors with your import.

In your file, label the group column to match your group category. For each subscriber, include their group names. To add a subscriber to more than one group name, separate each name with a comma and a space.

For example, if you have a Newsletter Preferences group category and the group names are Student Events, News, and Donations, format the Preferences cell for someone in all three groups as shown.

Student Events, News, Donations

Format list fields for groups

Download a Sample Import File

If you need help, try our sample import file as a starting point. The sample file contains columns for a basic import that includes subscriber email address, first name, and last name. Each column in the file corresponds to a field in your MailChimp list.

Download the sample CSV file, and replace the sample data with your subscriber data. You can also add more columns to the file, like zip codes or birthdays. Follow the format guidelines for different types of information, to update your MailChimp list correctly.

Sample File

Click the link to download the sample CSV import file. For best results, open the file in a spreadsheet program like Excel or Google Sheets.

Sample CSV Import File

After you update the file with your subscriber information and save it, learn how to import it into MailChimp.

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