What is an SSH key fingerprint calculator?

An SSH key fingerprint calculator computes the SHA-256 and MD5 fingerprints of an SSH public key. Fingerprints uniquely identify a key and are used to verify key identity on servers, GitHub, GitLab, and cloud providers.

How is the SSH key fingerprint calculated?

The fingerprint is computed by hashing the raw binary key blob (Base64-decoded RFC 4253 wire-format bytes). SHA-256 is displayed as SHA256:base64url; MD5 as colon-separated hex.

Is it safe to paste my SSH public key into this tool?

Yes. SSH public keys are designed to be shared. All processing happens in your browser - your key is never sent to any server. Never paste your private key into any online tool.

What SSH key types are supported?

ssh-rsa, ssh-ed25519, ecdsa-sha2-nistp256/384/521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com, and ssh-dss. Multiple keys can be processed at once.

SSH Key Fingerprint Calculator

Calculate the SHA-256 and MD5 fingerprints of any SSH public key instantly with our free SSH key fingerprint calculator. Supports ssh-rsa, ssh-ed25519, ECDSA, and FIDO2 security key types. Paste one or more public key lines and get fingerprints in the exact format used by OpenSSH, GitHub, and GitLab - no signup required.

Calculate SSH Key Fingerprints

Paste one or more SSH public key lines and click Calculate Fingerprints to instantly compute the SHA-256 and MD5 fingerprints for each key. Supports ssh-rsa, ssh-ed25519, ecdsa-sha2-nistp256/384/521, and FIDO2 security key types. All processing runs locally in your browser - your keys never leave your device.

SSH Public Key Input

Supported Key Types

ssh-rsa- RSA (2048, 3072, 4096-bit)

ssh-ed25519- Ed25519 (256-bit, recommended)

ecdsa-sha2-nistp256- ECDSA P-256

ecdsa-sha2-nistp384- ECDSA P-384

ecdsa-sha2-nistp521- ECDSA P-521

[email protected]- Ed25519-SK (FIDO2 hardware key)

[email protected]- ECDSA-SK P-256 (FIDO2)

ssh-dss- DSA (legacy, not recommended)

Why Use Our SSH Key Fingerprint Calculator?

Instant SSH Key Fingerprint Calculation

Our SSH key fingerprint calculator computes both SHA-256 and MD5 fingerprints instantly in your browser. Paste any SSH public key line and get the fingerprint in the exact format used by OpenSSH, GitHub, GitLab, and cloud providers - no waiting, no server round-trips.

All Key Types Supported

Calculate SSH key fingerprints for all modern and legacy key types: ssh-rsa, ssh-ed25519, ecdsa-sha2-nistp256/384/521, and FIDO2 security key types (sk-ssh-ed25519, sk-ecdsa-sha2-nistp256). Process multiple keys at once by pasting them on separate lines.

Secure SSH Key Fingerprint Calculator Online

All SSH key fingerprint calculations happen locally in your browser using the Web Crypto API. Your SSH public keys never leave your device, ensuring 100% privacy when you use our SSH key fingerprint calculator online.

SSH Key Fingerprint Calculator - No Installation

Use our free SSH key fingerprint calculator directly in your browser with no downloads, no plugins, and no account required. Upload a .pub file or paste key lines directly - works on any device, anytime.

Common Use Cases for SSH Key Fingerprint Calculator

Verifying SSH Key Identity

Compare the SSH key fingerprint shown by your server during first connection against the expected fingerprint to confirm you are connecting to the right host. Our SSH key fingerprint calculator lets you pre-compute the fingerprint from a known public key for safe comparison.

GitHub & GitLab Key Verification

GitHub and GitLab display SSH key fingerprints in account settings for verification. Use our SSH key fingerprint calculator to compute the SHA-256 fingerprint of your local public key and confirm it matches the fingerprint shown in your account.

Cloud Provider Key Management

AWS EC2, Google Cloud, and Azure display SSH key fingerprints when you upload public keys. Calculate the fingerprint of your key with our tool to verify the correct key is registered before launching instances or connecting to virtual machines.

SSH Key Auditing & Inventory

Security teams use SSH key fingerprints to audit and inventory authorised keys across servers. Our SSH key fingerprint calculator lets you quickly fingerprint all keys in an authorized_keys file to identify unknown or unauthorised entries.

CI/CD Pipeline Key Verification

Verify that the SSH deploy keys configured in your CI/CD pipelines (GitHub Actions, GitLab CI, Jenkins) match the expected keys. Calculate fingerprints from your .pub files and compare them against the fingerprints shown in your pipeline settings.

SSH Certificate & Known Hosts Management

System administrators use SSH key fingerprints to manage known_hosts files and SSH certificate authorities. Our SSH key fingerprint calculator helps verify host key fingerprints and validate CA public keys during SSH infrastructure setup.

Understanding SSH Key Fingerprints

What is an SSH Key Fingerprint?

An SSH key fingerprint is a short, human-readable hash of an SSH public key that uniquely identifies it. Because SSH public keys are long Base64 strings, fingerprints provide a compact representation that is easy to compare and verify. OpenSSH computes fingerprints by hashing the raw key blob bytes - the binary wire-format data defined in RFC 4253 - using either SHA-256 (the modern default since OpenSSH 6.8) or MD5 (the legacy format). Our SSH key fingerprint calculator uses the same method, computing fingerprints directly from the decoded key blob in your browser.

How Our SSH Key Fingerprint Calculator Works

Paste Your SSH Public Key: Paste one or more SSH public key lines in the standard OpenSSH format (e.g. from your ~/.ssh/id_ed25519.pub file) or upload a .pub file directly. Multiple keys on separate lines are all processed at once.
Instant Browser-Based Calculation:Click Calculate Fingerprints and the tool decodes the Base64 key blob, then computes the SHA-256 fingerprint using the browser's Web Crypto API and the MD5 fingerprint using a pure-JavaScript implementation. Your SSH keys never leave your device.
Copy and Verify: Each result card shows the SHA-256 fingerprint (in the SHA256:base64url format used by OpenSSH), the MD5 fingerprint (colon-separated hex), key type, key size, and comment. Click the copy icon next to any value to copy it instantly.

SHA-256 vs MD5 Fingerprints

SHA-256 (recommended): The default fingerprint format since OpenSSH 6.8 (2015). Displayed as SHA256:base64url without padding. This is the format shown by ssh-keygen -l, GitHub, GitLab, and most modern SSH tools.
MD5 (legacy): The original fingerprint format, displayed as 16 colon-separated hex bytes (e.g. aa:bb:cc:dd:...). Still used by some older systems, AWS EC2 key pairs, and legacy SSH clients. MD5 is cryptographically broken but remains in use for fingerprinting only.
Fingerprint scope: Both fingerprints are computed over the raw key blob bytes, not the Base64 string or the full public key line. This means the comment field does not affect the fingerprint.
Uniqueness: Two different keys will always produce different fingerprints. The same key will always produce the same fingerprint regardless of the comment or formatting of the public key line.

Important Notes on SSH Key Security

SSH key fingerprints are computed from the public key only and are safe to share. Never paste your private key (the file without the .pub extension) into any online tool. Our SSH key fingerprint calculator only accepts and processes public key lines - it cannot extract or derive private key material from a public key. Always keep your private keys secure and never share them.

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Frequently Asked Questions About SSH Key Fingerprint Calculator

An SSH key fingerprint calculator is a tool that computes the SHA-256 and MD5 fingerprints of an SSH public key. Fingerprints are short hashes that uniquely identify a key and are used to verify key identity when connecting to servers, registering keys on GitHub or GitLab, and auditing authorized_keys files. Our SSH key fingerprint calculator runs entirely in your browser.

The fingerprint is computed by hashing the raw binary key blob - the Base64-decoded wire-format bytes defined in RFC 4253. The SHA-256 fingerprint is displayed as SHA256:base64url (without padding), which is the format used by OpenSSH since version 6.8. The MD5 fingerprint is displayed as 16 colon-separated hex bytes, the legacy format used by older SSH clients and AWS EC2.

No. The fingerprint is computed only from the key blob bytes (the Base64-encoded middle field of the public key line). The key type prefix and the comment at the end are not included in the fingerprint calculation. This means you can change or remove the comment without changing the fingerprint.

Yes. SSH public keys are designed to be shared - they are the non-secret half of the key pair. Our SSH key fingerprint calculator processes your public key entirely in your browser and never sends it to any server. Never paste your private key (the file without the .pub extension) into any online tool.

Our SSH key fingerprint calculator supports all modern and legacy OpenSSH key types: ssh-rsa (RSA), ssh-ed25519 (Ed25519), ecdsa-sha2-nistp256/384/521 (ECDSA), [email protected] (Ed25519-SK FIDO2), [email protected] (ECDSA-SK FIDO2), and ssh-dss (DSA legacy). Multiple keys of different types can be processed at once.

Run ssh-keygen -l -f ~/.ssh/id_ed25519.pub (replace with your key file path). By default this shows the SHA-256 fingerprint. To see the MD5 fingerprint, run ssh-keygen -l -E md5 -f ~/.ssh/id_ed25519.pub. Our SSH key fingerprint calculator produces identical results to these commands.

GitHub displays SHA-256 fingerprints in the SHA256:base64url format. Older SSH clients may display MD5 fingerprints in the colon-separated hex format. Both fingerprints are computed from the same key blob - they just use different hash algorithms. Our SSH key fingerprint calculator shows both formats so you can compare against either.

Yes. Paste multiple SSH public key lines (one per line) into the input and click Calculate Fingerprints. The tool processes all lines simultaneously and displays a separate result card for each key, showing the SHA-256 fingerprint, MD5 fingerprint, key type, key size, and comment.

Yes! Our SSH key fingerprint calculator is 100% free with no signup, no account, and no usage limits. Calculate SSH key fingerprints for any number of keys as many times as you need - completely free, forever.