DER (Distinguished Encoding Rules) is the binary form of an ASN.1 certificate or key. It is the same data as PEM but without the Base64 encoding and headers.

How do I know which header to use?

Use CERTIFICATE for TLS/SSL certificates, PRIVATE KEY for PKCS#8 private keys, and PUBLIC KEY for SPKI public keys.

DER to PEM Converter

Upload a .der file and convert it to PEM format with the appropriate header and footer.

Header Type

Drop a .der file here or click to upload

Related Tools

#PEM to DER Converter

Convert a PEM certificate or key to binary DER format and download the .der file.

#SSL Certificate Decoder

Paste a PEM certificate and decode its subject, issuer, validity dates, SANs, and more.

#PEM Key Parser

Paste a PEM private or public key to detect its type, algorithm, and key size.

FAQ

What is a DER file?: DER (Distinguished Encoding Rules) is the binary form of an ASN.1 certificate or key. It is the same data as PEM but without the Base64 encoding and headers.
How do I know which header to use?: Use CERTIFICATE for TLS/SSL certificates, PRIVATE KEY for PKCS#8 private keys, and PUBLIC KEY for SPKI public keys.

Upload a binary DER file, Base64-encode it, and wrap it with -----BEGIN CERTIFICATE----- / -----END CERTIFICATE----- headers to produce a PEM file. Choose the header type (CERTIFICATE, PRIVATE KEY, PUBLIC KEY) if the file type is known. Copy or download the resulting PEM.