Convert PEM to DER Certificate Online
PEM and DER are the two most common certificate encoding formats. PEM is a Base64-encoded text format with header and footer lines, while DER is the raw binary encoding of the same ASN.1 structure. Many Java keystores, Android apps, and older systems require DER format, while most web servers and command-line tools use PEM. This tool converts PEM-encoded certificates and keys to DER binary format directly in your browser, with no server upload required. The resulting DER file can be downloaded immediately and used with Java keytool, openssl, or any system that requires binary certificate encoding. This is particularly useful for Java developers, mobile app developers, and anyone working with legacy PKI infrastructure.
Strips the PEM header/footer and Base64-decodes the body to binary DER. The file is created in your browser and downloaded directly — nothing is uploaded.
FAQ
- What is the difference between PEM and DER?
- PEM is a Base64-encoded text representation of a DER certificate, wrapped in -----BEGIN/END----- header lines. DER is the raw binary form. Both encode the same certificate data.
- Which format does Java use?
- Java's keytool and many Java libraries use DER format for importing certificates and keys, though Java also supports PEM through libraries like Bouncy Castle.
- Can I convert private keys as well as certificates?
- Yes. The converter handles PEM-encoded certificates, private keys, and certificate chains, converting all to their DER equivalents.