After creating a list in MailChimp you can import your opted-in subscribers or contacts. We offer many options for importing your list including uploading a CSV or tab delimited text file, copying and pasting from Excel, or importing directly from an integrated application. If you're using an application that doesn't currently integrate with MailChimp, refer to that program's support documentation or help team for assistance with getting a CSV file of your contacts. If you're trying to import your Mac Address Book contacts, be sure to check out our handy app called Chimport for help with that.

In this article:

Import Your List

When you import a new list to your MailChimp account, we scan your file and remove any duplicate email addresses from the import. In addition, when you upload new members to an existing list, we scan for duplicates, bounces, and unsubscribes that are already stored in the list you're importing to.

Lists in MailChimp are independent of each other and don't share information, so we can't detect duplicates, bounces, or unsubscribes across multiple lists. If you manage a customer list outside of MailChimp, you want to import it into the same list in MailChimp so we can detect any duplicates and keep track of bounces and unsubscribes for you automatically.

Importing from a file on your computer

If you have a CSV or tab delimited file with all your contacts, this file can be uploaded directly into the MailChimp list. If you're working with an Excel file, one that has a .xls extension, you must use the Copy/Paste from Excel option on the import screen. Follow the steps below to upload your contacts from your computer.

  1. Navigate to the Lists page.
  2. Click the drop down for the list you're working with and select the Import option.
  3. Select Upload from CSV if using a CSV file or Copy/Paste from Excel if working with an Excel file.
    Select Upload from CSV or Copy/Paste from Excel
  4. Depending on the method you're using, you either need to select the file you want to import using the Browse button or copy and paste in your contacts from an Excel file.
  5. Click the Upload List button to import your contacts.
    Click Upload List to import contacts

The Auto-update option allows you to update info for subscribers and add new fields to your list. If you're uploading a new list, there's no need to check the Auto-update option.


If you're using the Auto-update feature to update subscriber information, be aware that when you map columns in your import file to lists fields in your account, any data you're importing will override data already in your list for that field. For example, if you matched a blank column to an existing list field with data stored in it, that data would be erased.

Importing from an integrated application

In addition to importing your contacts from your computer, we also have several options for adding contacts through integrated applications on the import screen. To see what options are available just follow the steps below.

  1. Navigate to the Lists page.
  2. Click the drop down menu for the list you're working with and select Import.
  3. Select the available application you'd like to import from.
    Select application to import from
  4. Click the Import List button once you've followed the prompts for the integration to import your list to our system.

Importing contacts using MailChimp's API

If you have a database or other application that's not currently integrated by default within MailChimp, there are more options. First, be sure to check out our excellent directory of third party integrations to see if anyone has developed a solution using MailChimp's API that could suit your integration needs. If there are no integrations that offer exactly what you're looking for, our API is free to use and your developer could create a custom integration between your external database and a MailChimp account. Using the API is definitely something that only experienced programmers should dabble in, so if you don't currently have a developer on staff that can help with this be sure to reach out to one of our for-hire MailChimp Experts to lend a hand.

Match Your Fields

Once your file has been imported into MailChimp, match the columns from your file to fields in your list. You can choose to skip certain columns, or customize the field names and types.

  1. Use the drop-down menu above each column to match the fields to existing ones on your list, or create a new column. If you have unnamed columns, you can select a different field from the drop down.
  2. If you want to add a new field, select – New Column Name – from the drop-down to name the column and select the type for this field.
  3. Click Ok to move to the next field or Skip if you don't want to add the field to the list.
  4. Once you've matched all your columns, a success notification will appear. Click the button to upload and complete your import.


  • If the list you plan to import contains previously collected opt-in data such as IP address, opt-in date, and opt-in time stamp, be sure to include those columns in the file you import into MailChimp so that you don't lose that important permission information. When you import the file, those fields will display on the mapping step, as shown below.
    Previously mapped fields
    Opt-in information can be added for only new subscribers to your list. The opt-in information for existing subscribers on your list cannot be overwritten.

Guidelines For Field Formatting

When importing a new list or updating an existing list, some fields need to be formatted a specific way to be uploaded properly. It's also important to make sure the file you're importing is encoded in UTF-8 format. Using the proper formatting and encoding ensures all of your subscriber information gets uploaded successfully and yields the most consistent results. If you've already created fields in your list, you can check the type of each field by following the steps below.

  1. Navigate to the Lists page.
  2. Click the list's drop-down menu and select Settings.
  3. Click List fields and *|MERGE|* tags.

The Field type is shown next to each Field label. Below we detail the requirements for various field types.


When you add an address field to your signup form, it appears to add several fields for entering data. However, you don't need to add a separate column in your import file for each portion of the address. Instead, separate each item in the address with double spaces. An address like this:

512 Means St.
Suite 400
tlanta, GA 30318 USA

would look like this in your file (where "spacespace" is two spaces, not the word space!):

512 Means St.spacespaceSuite 404spacespaceAtlantaspacespaceGAspacespace30318spacespaceUSA

If a subscriber doesn't have an apartment or suite (or a second street address line), you can skip that line and the system sorts the fields correctly.

It's important that you add the country at the end of each address. Especially if you want to segment by zip code.


On your signup form, you can choose whether to accept Month/Day or Day/Month for a birthday field. When importing, though, make sure birthdays are in Month/Day format:


Birthday fields are preferred to a regular date field if you want to send something like an automatic birthday message to your subscribers.


Date fields should use one of the following formats where "MM" is the two digit month, "DD" is the two digit day of the month, and "YYYY" is the four digit year. MailChimp attempts to convert the date field to match the account's default date format. Using the ISO standard format(YYYY-MM-DD) yields the most consistent results when importing into a date field.





An image field allows you to specify an image URL for an image hosted online somewhere. Be sure to include the full address with the "http://" at the beginning.


U.S. phone numbers should be in the following format with no spaces, parenthesis or dots.


International numbers generally won't fit this format. If you have international subscribers, choose the international phone number option when creating a phone number field on the sign up form.


Website fields need to include the full URL of the subscriber's website, including the http://.

Zip Code

A zip code field can only contain five digits. International zip codes that use anything other than numbers or are longer than 5 digits won't work in a zip code field, so if you have international subscribers, a text field should be used instead.


Groups should be created before you import your list. Here's how to add groups to a list. Once those groups are added to your list, just follow the our formatting recommendations below to make sure all your group info is imported successfully.

  • The Group Title should be the column heading. In that column, you want to list the subscriber subgroups in the same cell. If a group field uses checkboxes, more than one subgroup can be chosen for a subscriber. In this case you need to place a comma between the different subgroups that subscriber belongs to. For example, if your subscribers can choose from Puppies, Kitties and Snails and a particular subscriber chooses all three then it should look like this:
    Puppies, Kitties, Snails
  • Subgroup names are separated by commas, so if one of the choices contains a comma the comma would have to be removed or escaped. You can escape a comma by adding a slash immediately before it. So a group named New products, promotions and events would look like this in your file:
    New products, promotions and events
  • Group options are case-sensitive and must be spelled consistently in MailChimp and in your imported list

What to do next

Now that you've created a list and added subscribers to it, you're probably ready to create a campaign to send to them. If you're already familiar with the basic steps to create a new campaign, follow our tips and best practices for editing your campaign.


There is technically no maximum number of recipients you can have in any of your MailChimp lists, but if you're in the several hundred thousand range you want to speak with our high volume team.

MailChimp's a browser-based application, so there are a few things you should consider when you have a large list:

  • Uploading a very large list into MailChimp can take a while. If you're having trouble have your programming team look into syncing via the MailChimp API.
  • If you do import an extremely large list into MailChimp (by extremely large, we mean more than a few hundred thousand recipients), keep in mind that some pages may render slowly. For example, those pie charts take longer to generate, because there's lots more to calculate.

To get around the some of the technical issues involved with large lists, some developers simply link to integrate their account with their database via the MailChimp API, so they don't even have to log in to MailChimp.

List import notifications are sent from If you have trouble getting those notifications, add to your address book.

Undo a List Import

You can undo a list import for any reason, such as to resolve a compliance issue, from the Import History page for your list.

  1. Navigate to the Lists page.
  2. Click the drop-down menu for the list you want to work with and select Import.
  3. Under the Latest Import heading, click the View import history for this list link.
  4. Click Undo for the list import.
  5. Type UNDO into the confirmation pop-up window, then click Undo.

After you confirm the action, the list import is marked as undone on your list's Import History and displays the time and date that the list import was undone.

This feature is limited to certain user levels. You can see your user level on the Users & Account Details page and this article explains what each level can access in the account.

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