Email hash
Hash an email address in your browser with SHA-256, SHA-1, SHA-512, MD5 (Gravatar), or HMAC-SHA-256. Nothing is uploaded.
Enter an email, then Hash.
How to hash an email address
- Type or paste the address. Leave Lowercase and trim on unless you need the exact bytes.
- Click Hash. SHA-256 is the default digest for logs and lookups.
- Copy the hex string you need. Add an HMAC secret only when the receiver also has that key.
SHA-256 vs Gravatar MD5
Most new systems hash emails with SHA-256 after lowercasing. Gravatar still uses MD5 of the trimmed, lowercase address. This page shows both so you can match either convention. HMAC-SHA-256 is for when a shared secret must be mixed in; the secret stays in this tab.
Nothing is uploaded
Hashing uses Web Crypto (and a local MD5 routine for Gravatar). The address is not posted to Geek University and is not sent to Gravatar. Need mail-server keys instead? Use the DKIM key generator. More utilities live on tools.
Email hash FAQ
Does this email hash tool upload the address?
No. Digests are computed in your browser. We do not log the email you type.
Should I lowercase the email first?
Yes, for almost every lookup. RFC-style addresses are compared case-insensitively. Turn the checkbox off only when you must hash the exact original bytes.
What is the Gravatar hash?
MD5 of the trimmed, lowercase email, as hex. This page shows that digest so you can build a URL yourself. It does not fetch a Gravatar image.
When do I use HMAC-SHA-256?
When both sides share a secret and a plain digest is not enough. Leave the secret blank if you only need SHA-256.
Is the email hash tool free?
Yes. There is no account.