Email list template: CSV import files for Mailchimp, Klaviyo, HubSpot and more
An email list template is a spreadsheet with the column headers an email platform expects, so the import maps cleanly. Pick Mailchimp, Klaviyo, HubSpot, Instantly, Smartlead or lemlist, download the CSV template, and open it in Excel or Google Sheets. Then check your filled file here for a missing email column, bad headers or the wrong separator.
Where are you importing the list?
Header row
Email Address,First Name,Last Name,Tags
- An email address column is required, with one address per contact. Labels are free: you match each column to a field during import.
- Tags go in one column called Tags, comma separated; wrap a tag that contains a comma in double quotes.
- SMS phone numbers must be in E.164 (+14155550123). Dates: YYYY-MM-DD. Countries: two-letter codes (GB, not UK).
From Mailchimp: Format guidelines for your import file, checked 17 October 2026. The CSV opens in Excel and Google Sheets (File, Import).
Sample result
This 3-row file has 1 warning: one row has no email address.
- File check
- 3 rows
- Columns
- 4
- Rows with an email
- 2
What this means for you
Fix that row before importing so the platform doesn't skip or reject it.
- Headers each platform's help centre names
- Checks your file for a missing email column
- Catches an address in the header row
- Spots semicolon-separated files
- Template
- Import
- Headers
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I make an email list template for an import?
- Choose where the list is going: Mailchimp, Klaviyo, HubSpot, Instantly, Smartlead or lemlist.
- Download the CSV template, or copy the header row and paste it into row 1 of a Google Sheet.
- Fill one contact per row, keeping the email column, then save or download it as CSV (UTF-8 if names have accents).
- Paste or upload the file under Check my file to catch a missing email column, a header problem or a wrong separator before you import.
Example
- You enter
- Mailchimp chosen, then a 3-row file checked where one row has no email address.
- You get
- The template's header row (Email Address, First Name, Last Name, Tags) and a file check with 4 columns, 2 rows with an email and 1 warning for the row with no address.
- Limits
- Six platforms are covered; the file check runs in your browser and an uploaded file can be up to 25 MB.
How do I create an email list in Excel or Google Sheets?
Put the column names in row 1, one contact per row below, and save as CSV. Every platform here needs an email column; first name, last name and company are the usual extras, and they become merge fields like {{firstName}} in your copy. Keep one address per cell: a cell holding two addresses imports as one invalid contact.
In Excel, use File, Save As, CSV UTF-8 (comma delimited), which Instantly's CSV import guide asks for by name. In Google Sheets, File, Download, Comma-separated values. If Excel on your computer uses semicolons as the list separator, Klaviyo's troubleshooting guide says the file will land in one column; the checker above flags that.
What format does Mailchimp need for a CSV import?
Mailchimp needs an email address column with one address per contact; every other field is optional. Its format guidelines let you label columns freely and match them to fields during import, and ask for tags in a single Tags column, comma separated, dates as YYYY-MM-DD and SMS phone numbers in E.164.
Klaviyo is stricter about order: its import guide wants Email, Email Address or Phone Number as the first column and files of 50 MB or less. HubSpot's import file rules ask for an Email column for contacts, one sheet, fewer than 1,000 columns, and headers that match HubSpot properties.
What columns does a cold email CSV need for Instantly, Smartlead or lemlist?
An email column, plus whatever you personalise with. Instantly makes Email mandatory and caps headers at 20 characters and 50 variables per upload. Smartlead's mapping guide maps Name, Email and Location automatically and keeps up to 40 custom variables per lead. lemlist's CSV import guide uses the email as each lead's unique ID and treats header names as case-sensitive variables.
Every extra column becomes a variable your copy can use, so name them for how you will write them: companyName reads better in a template than Column 7. The CSV merge tool combines lists from several exports into one file first.
Why verify a list before importing it?
Because the import only checks columns; the first time anyone finds out an address is dead is when your send bounces. Bounces count against the sending account, and email platforms limit or suspend accounts that bounce too often. A template guarantees the file is shaped right, not that the people in it still have those mailboxes.
For a free first pass, the list health check catches bad syntax and domains that can't receive mail, and remove duplicate emails stops one person getting two copies.
Which platforms are strictest about the CSV?
| Email column | Header rules | Size limit | |
|---|---|---|---|
| Mailchimp | Required, any label | Label clearly; tags in one column | Not stated in the guide |
| Klaviyo | Must be first: Email, Email Address or Phone Number | Use Klaviyo property names | 50 MB |
| HubSpot | Email (contacts) | Match HubSpot properties; <1,000 columns | 20 MB free, 512 MB paid |
| Instantly | Mandatory | ≤20 characters, no duplicates, ≤50 variables | Not stated in the guide |
| Smartlead | Mapped automatically | Up to 40 custom variables per lead | Not stated in the guide |
| lemlist | Required, unique ID | Case-sensitive variable names | Not stated in the guide |
Who uses this tool, and for what?
- Small businesses
- Start a customer list in the right shape for Mailchimp or Klaviyo instead of fixing columns at import time.
- Cold emailers
- Build lead sheets with the exact headers Instantly, Smartlead or lemlist map automatically, so merge fields work on the first send.
- CRM admins
- Check a contact export against HubSpot's import rules before it fails on row 40,000.
- Agencies
- Hand clients a template per platform so the lists they send back import without rework.
What can’t this tool tell you?
- Header rules are from each platform's help centre as read on 17 October 2026; platforms change them, and their mapping screen has the final say.
- The checker reads columns and rows; it doesn't validate custom field values such as dates or consent values.
- Brevo, ActiveCampaign and others aren't listed yet because we couldn't confirm their import rules from their own docs.
- It checks that an email column exists, not that the addresses in it can receive mail.
Common questions
- How to create a mailing list template?
- Put the column names your platform expects in row 1, Email first, then First Name, Last Name and any fields you'll personalise with, and save as CSV. The templates above have the headers already set for each platform.
- How to create an email list in Google Sheets?
- Paste a template's header row into row 1, add one contact per row, then use File, Download, Comma-separated values to get a CSV any email platform can import.
- How to upload a CSV file to Mailchimp?
- Make sure the file has an email address column with one address per row, then use Mailchimp's contact import and match each column to a field. Mailchimp's format guidelines cover tags, dates and phone numbers.
- How to import an email list into Klaviyo?
- Save a CSV with Email as the first column and comma separators, under 50 MB, then go to Audience, Lists & segments, open the list and choose Import contacts. Add a consent column if the list mixes subscribed and unsubscribed contacts.
- How to import contacts into HubSpot from Excel?
- HubSpot takes .xlsx, .xls or .csv with one sheet and a header row, and contacts need an Email column. Name the headers after HubSpot properties, such as First Name and Last Name, so they map automatically.
- How to save Excel as CSV UTF-8?
- File, Save As, then choose CSV UTF-8 (comma delimited) as the file type. Plain CSV in older Excel versions can turn accented names into question marks.
Sources
- Mailchimp: Format guidelines for your import file
- Klaviyo: How to import subscribers to a list
- Klaviyo: Troubleshooting list imports
- HubSpot: Set up your import file
- Instantly: How to import leads via CSV
- Smartlead: How to map CSV columns in campaigns
- lemlist: How to import leads from a CSV file
- RFC 4180: CSV format
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? $9 one-time covers 2,500 emails, no subscription
One plan, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.