SSH Key Fingerprint Calculator
Paste an OpenSSH public key (authorized_keys line) to get its SHA256 fingerprint, key type, size or curve and comment — verify host keys and GitHub deploy keys without ssh-keygen.
About SSH Key Fingerprint Calculator
SSH Key Fingerprint Calculator parses an OpenSSH public key line and computes the same SHA256 fingerprint ssh-keygen -lf prints, plus the key type, size or curve and comment — in the browser, with the key never leaving your device.
How to use SSH Key Fingerprint Calculator
- 1Paste or type your input into the box above — a sample is pre-filled so you can try it instantly.
- 2Set any options on offer (mode, key, format) to match what you need.
- 3The result appears the moment you type — no button to press, no waiting.
- 4Click Copy to grab the output — SSH Key Fingerprint Calculator keeps everything on your device.
Why use SSH Key Fingerprint Calculator?
- ✓Matching a server's host-key prompt against the fingerprint published by your provider
- ✓Identifying which key in authorized_keys belongs to whom
- ✓Verifying the fingerprint of a deploy key before adding it to GitHub/GitLab
- ✓100% free with no sign-up, no watermark and no usage limits
- ✓Runs entirely in your browser — your text and keys are never uploaded, stored or logged
- ✓Works offline once loaded, with instant results and one-click copy
Frequently asked questions
How do I check an SSH key fingerprint?+
Paste the public key line (from id_ed25519.pub, authorized_keys or known_hosts) and compare the SHA256: value with the one shown by ssh-keygen -lf, your cloud console or the host-key prompt. A match means it is the same key; a mismatch on a host prompt can indicate a man-in-the-middle.
Which SSH key type should I use?+
Ed25519 — small, fast and immune to the nonce-reuse pitfalls of ECDSA. RSA remains fine at 3072+ bits for systems that need it; below 2048 bits is unacceptable, and DSA (ssh-dss) has been disabled by default since OpenSSH 7.0. The parser flags both weak cases.
Is it free to use?+
Yes — completely free with no sign-up, no account and no usage limits. There is no paywall, so you can encode, decode and convert as much as you like.
Is my data private and secure?+
Yes. This tool runs entirely in your browser using client-side JavaScript — your input is never uploaded to a server, stored or logged. Once the page has loaded you can use it offline, which makes it safe for tokens, keys and confidential data.
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