Meta Custom Audience email hasher
Hash emails with SHA-256 for Meta Custom Audiences. Lowercase, trim, skip duplicates, and download hashes only. Nothing is uploaded.
Paste emails, then Hash list.
How to use the Meta Custom Audience email hasher
- Paste one address per line or open a CSV with an email column. Leave lowercase and trim on.
- Click Hash list. 64-character hex values are copied through so you do not double-hash.
- Download the CSV of hashes and upload that file in Meta Ads Manager. Do not upload plaintext emails.
Meta hashing rules
Meta matches first-party lists on SHA-256 of the trimmed, lowercase email. This page locks SHA-256 and keeps that normalization on. The download is hashes only, which is what Ads Manager wants for a hashed email column.
Nothing is uploaded
Web Crypto runs in this tab. Geek University never sees the list. Typical lists up to 50,000 addresses or 2 MB are supported.
Meta Custom Audience email hasher FAQ
Is this for Meta Custom Audiences?
Yes. Use it to SHA-256 emails before you upload a hashed list in Meta Ads Manager.
Does Meta want plaintext emails?
Not in the hashed-audience file. Upload the hashes this page downloads.
Should I lowercase first?
Yes. Meta documents trim and lowercase before SHA-256. Leave that checkbox on.