What is a PEM JWK converter?
PEM is the classic Base64 key format with BEGIN/END headers used by OpenSSL and most certificate tooling, while JWK (JSON Web Key, RFC 7517) is the JSON representation used by JOSE, JWT and OAuth stacks. A converter lets the same key work in both worlds.
This tool imports SPKI and PKCS#8 keys — and re-wraps the legacy PKCS#1 and SEC1 formats automatically — then exports the matching JWK, or converts a JWK back into a standard PEM. Everything runs locally in your browser.
How to convert PEM to JWK
Paste your PEM key on the PEM → JWK tab and click Convert. The JWK is printed as pretty JSON on the right, ready to copy.
Public keys export as public JWK members (n/e for RSA, x/y for EC); private keys additionally include d and the other private members.
How to convert JWK to PEM
Switch to the JWK → PEM tab and paste the JWK JSON. The tool reads kty to detect RSA or EC and checks for the d member to tell private keys apart.
The result is a standard PEM: PUBLIC KEY (SPKI) for public keys and PRIVATE KEY (PKCS#8) for private keys.
Key information panel
After every conversion the panel shows the key type, algorithm, size in bits, and whether the key is public or private — useful for a quick sanity check.
Supported formats
PEM labels PUBLIC KEY, RSA PUBLIC KEY, PRIVATE KEY and EC PRIVATE KEY are accepted; RSA and EC keys on P-256, P-384 and P-521 are supported. Ed25519 and other types are not.