Certificate to CSR Command Generator
Paste an existing certificate and get a ready-to-run openssl command that creates a
matching CSR — reusing its subject and SANs. The certificate is read entirely in your browser.
New to this? Read the Certificate to CSR guide →
This command generates a brand-new private key. A certificate alone doesn't
contain its private key, so the CSR can't reuse the original key — running the command below
creates a new
.key and a matching .csr.
OpenSSL command
Needs OpenSSL 1.1.1 or newer (for -addext). Run it in a terminal where you want the new key and CSR saved.
Paste a certificate and press Generate command.