Compute HMAC-SHA256, HMAC-SHA384 or HMAC-SHA512 for UTF-8 text and a key.
Type or paste on the left — the result updates as you type.
The key is interpreted as UTF-8 text, not hex or Base64. The message and key remain in the browser.
Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.
Tool page updated: 2026-09-27
