PEM · DER · Base64 · PKCS#7
PEM ↔ DER converter
Drop a .der, .cer, .crt, .pem or .p7b file, or paste PEM or Base64, and download each object in the format you need. Bundles are split into separate files; nothing is uploaded.
Input
Any mix of certificates, CSRs, keys and PKCS#7 bundles. Binary files are converted to PEM here first.
The formats in brief
- PEM: Base64 text between
-----BEGIN …-----and-----END …-----lines, used by nginx, Apache, OpenSSL and most Linux software. Typical extensions: .pem, .crt, .key. - DER: the same data in binary, common on Windows and in Java. Typical extensions: .der, .cer.
- Base64: PEM without the header lines, as some APIs and control panels expect.
- PKCS#7 (.p7b, .p7c): a container that holds certificates, often a whole chain, but no keys. Windows and Java keystores import it.
Each object is recognised from its structure, so a mislabelled file still gets the right PEM header. To read the contents of a certificate, use the certificate decoder.
Frequently asked questions
Is a .crt file PEM or DER?
Either: the extension says nothing about the encoding. Open the file in a text editor; if it starts with -----BEGIN it is PEM, otherwise it is binary DER. The converter detects both.
Can it convert .pfx or .p12 files?
No. PKCS#12 files are protected with a password. Extract the certificate and key on your machine with openssl pkcs12 -in file.pfx -out file.pem -nodes, then paste the result here.
Why would I split a bundle?
Some servers and control panels want the certificate and the intermediates in separate fields or files. Splitting gives you one file per object, in the order they appear.