PEM ↔ DER Converter
Free online PEM to DER and DER to PEM converter. Convert SSL certificates, private keys, and CSR files between PEM (Base64 text) and DER (binary) formats instantly in your browser. Perfect for developers working with different server and application requirements. All conversion runs 100% client-side — your certificates never leave your browser.
📄 PEM = Base64 text with -----BEGIN----- headers (Linux, Nginx, Apache) 🔲 DER = Binary format (Windows IIS, Java, Android)
how to use
- 1.Select conversion direction: PEM → DER or DER → PEM
- 2.For PEM → DER: paste your PEM text or upload a .pem file
- 3.For DER → PEM: upload a .der or .crt binary file
- 4.Click Convert and download the result
frequently asked
What is the difference between PEM and DER?
PEM is a Base64-encoded text format wrapped with -----BEGIN----- headers, commonly used on Linux/Apache/Nginx. DER is a binary format commonly used on Windows and Java applications.
Which format does Nginx use?
Nginx uses PEM format. Windows IIS and Java keystores typically use DER or PKCS#12 format.
Can I convert private keys too?
Yes — the converter works with certificates, private keys, CSRs, and any PEM/DER encoded file.