Convert DER to PEM Certificate Online
DER is the binary certificate format used by Java keystores, many hardware security modules, and older PKI systems, while PEM is the text format required by most web servers, OpenSSL commands, and modern TLS configuration. When you have a DER certificate and need it in PEM format for Nginx, Apache, Let's Encrypt workflows, or OpenSSL inspection, this converter handles the transformation instantly. Upload the DER file and download a properly formatted PEM file with correct headers and line breaks. All processing runs entirely in your browser — your private keys and certificates never leave your device. This is essential for developers working across Java and non-Java environments, or when extracting certificates from Windows certificate stores.
FAQ
- Why would I need DER to PEM conversion?
- Common reasons include importing a Java-exported certificate into Nginx, using a Windows-exported DER cert with OpenSSL, and preparing a certificate for deployment to a Linux web server.
- Does this work for private keys?
- Yes. DER-encoded private keys (PKCS#8 or PKCS#1) are converted to PEM format with the correct -----BEGIN PRIVATE KEY----- or -----BEGIN RSA PRIVATE KEY----- headers.
- Is the output compatible with OpenSSL?
- Yes. The PEM output uses standard 64-character line wrapping and correct headers, making it directly usable with openssl commands and most web server configurations.