Import CSV Template and Profile + SMS Formatter for Klaviyo

How to fill the Klaviyo import CSV template

A Klaviyo import CSV template is simply a CSV with the right columns: Klaviyo's guide to importing subscribers to a list describes what each one needs. This tool builds that file from whatever you have — an export from another email tool, your store or a CRM — with the consent columns in Klaviyo's exact wording, which is where most imports go wrong.

1. Export your contacts as a file. Any CSV or Excel file works, as long as it has emails or phone numbers.
2. Check the matched columns. Email, phone, names and address are found on their own. So are status columns such as Email Status, Accepts SMS Marketing or Opt-in Date.
3. Set the default country and date order. The country is only used for numbers typed without a country code. The date order matters for files from the UK, Europe or Australia.
4. Decide what happens to unsubscribes. By default they go into their own file, so nobody who opted out is imported as a subscriber by mistake.
5. Download and import. Check the problem list first: it shows every phone number removed and every SMS consent that could not be kept.

What the finished file contains

• Email first — or Phone Number first when some rows have no email, as Klaviyo advises.
• Phones in E.164, like +14155550132. A number that can't be read is removed, because one invalid phone makes Klaviyo skip the whole row, email included.
• Consent in Klaviyo's words. “yes”, “subscribed”, “true” or “1” become Subscribe; “no” or “pending” stay blank, which Klaviyo reads as never subscribed.
• SMS consent only where it can work. It is removed for rows without a phone number and for numbers from countries missing from Klaviyo's SMS country list.
• Dates as YYYY-MM-DD HH:MM:SS, the format Klaviyo recommends, and only for people marked Subscribe.
• One row per email. Klaviyo reads only the first row of a repeated email or phone. Rows with the same email are merged; when two emails share one phone (a family line), both people stay and the phone stays on the first one only.

How to import the CSV into Klaviyo

1. Pause list-triggered flows. Set flows triggered by the target list, and SMS welcome flows, to manual first.
2. Open the list. Go to Audience › Lists & segments and open your list, or create a new one.
3. Upload the file. Choose Manage list › Import contacts › Upload, pick the CSV and click Next.
4. Check the mapping. Each column should point to a Klaviyo property. Columns that already use Klaviyo's names map by themselves; custom ones become new fields.
5. Import, then wait. Klaviyo emails you when the import is done. Wait at least two hours after an SMS import before you turn flows back on.

Common Klaviyo import errors

All columns imported as a single field

The file uses semicolons, which non-English Excel often does. This tool reads semicolon files and always writes commas.

Duplicate Unique ID and Missing Unique ID

Klaviyo skips repeated emails or phones after the first row, and rows with neither. Duplicates are merged here, and rows without an identifier go to the left-out file.

Klaviyo phone number format errors

A number like (415) 555-0132 has no country code. It gets one from the row's country or your default country, then E.164.

SMS subscribers imported without SMS consent

Klaviyo only applies SMS consent for countries where it has a sending number set up, and only when an Owner or Admin runs the import. Don't add a column called “Subscribed to SMS” or a generic “consent” column — Klaviyo asks you not to.

Incorrect date or timestamp formatting

Klaviyo only documents year-month-day and month/day/year dates, so day-first dates such as 19/10/2025 must be converted. Pick “Day/month/year” above so they are rewritten as 2025-10-19 00:00:00.