Add gender to Mailchimp subscribers
Add a GENDER audience field, fill it for every new subscriber from FNAME or the email address, and use it in segments with a probability threshold. Your current audience is enriched once through an export and import.
100 free credits every day. No card.
Add two audience fields
In Audience → Settings → Audience fields and *|MERGE|* tags, add a text field with the merge tag GENDER and a number field with the tag GENDERPROB. Subscribers without an answer keep an empty GENDER value.
Segment on both: GENDER is female and GENDERPROB is greater than 89, for example. A segment on the label alone puts every low-confidence guess into it.
For salutations, use conditional merge tags that fall back to a neutral greeting when GENDER is empty. Most lists contain role addresses and initials, and those should get the neutral version rather than a guess.
Zapier: New Subscriber → Find Gender → Add/Update Subscriber
Add NameGender to your Zapier account with the invitation link on this page. Trigger: Mailchimp, New Subscriber, on your audience. Action: NameGender, Find Gender, with the FNAME merge field as the name. Action: Mailchimp, Add/Update Subscriber, on the same audience with the subscriber’s email, Gender in GENDER and Probability in GENDERPROB.
Many sign-up forms ask only for an email. Then set the NameGender step’s type of value to Email and map the email address; the part before the @ is read, so jane.doe@example.com becomes Jane.
A three-step Zap needs a paid Zapier plan. In Make: Mailchimp’s watch-subscribers trigger, NameGender’s Get Gender from an Email Address, then Mailchimp’s add-or-update-subscriber module.
Enrich the existing audience once
Export the audience as CSV, upload it in the NameGender dashboard and pick the First Name column, or the Email Address column when first names are sparse. Check the estimated cost before starting.
Import the result into the same audience with “update existing contacts” switched on and map the gender and probability columns to GENDER and GENDERPROB. From then on the Zap only handles new subscribers.
Questions
Can I personalise a subject line with it?
Yes, with conditional merge tags. Keep a neutral fallback for empty GENDER values.
Does an empty FNAME break the flow?
No. Use the email address as input instead, or both in two paths of the Zap.
What about info@ or team@ subscribers?
They are role addresses and come back unknown. They still cost a credit.
Is inferred gender personal data under GDPR?
Treat it as personal data: mention the enrichment in your privacy notice and use it for segmentation and wording, not for decisions about a person.
Related pages
Write a gender custom property to new Klaviyo profiles from the first name or email, and build segments that only use confident answers.
Detect gender from an email address. The exact local-part transform, how role addresses and initials are handled, and the pre-filter that saves credits.
Append a gender column to a customer list, CRM export or lead database, with a confidence field you can filter on and no monthly reset on purchased credits.
Reading the gender field alone discards everything that says whether to believe it. What each response field means and the thresholds behind confidence.
Check it against your own list
Every number on this page is reproducible with a free key. If your data breaks it, that is the more interesting result.