Certificate tools

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Certificate Converter

Convert certificates between different formats: PEM, DER, PKCS#7/P7B, and PKCS#12/PFX

Input Certificate

Drop certificate file here or click to browse

Output Format

Supported Certificate Formats

Input Formats

  • PEM Format: Base64 encoded with headers (-----BEGIN CERTIFICATE-----)
  • DER Format: Binary ASN.1 encoded certificates
  • PKCS#7/P7B: Certificate chains and bundles
  • PKCS#12/PFX: Certificate and private key bundles
  • Base64: Raw base64 encoded certificate data

Output Formats

  • PEM: Text format for web servers (Apache, Nginx)
  • DER: Binary format for Java applications
  • PKCS#7: Certificate chains for Windows/IIS
  • PKCS#12: Complete bundles for client authentication
  • Base64: Raw base64 for embedding in code

Security Notice

Conversions are processed in memory on our server and are never logged or stored. If your file contains a private key (PFX/P12), it is used only for the conversion you requested and then discarded.

How to Convert Between Certificate Formats

Every conversion below works with the converter above — upload the file, pick the target format and download the result. The equivalent OpenSSL command is included if you prefer the command line.

Convert PEM to PFX (PKCS#12)

Combine a PEM certificate and its private key into a single password-protected PFX/P12 bundle — the format Windows IIS and many load balancers import. Upload the PEM certificate above, choose PFX as the target format and add the private key when prompted.

openssl pkcs12 -export -in certificate.pem -inkey private.key -out certificate.pfx

Convert PFX to PEM

Extract the certificate (and optionally the key and chain) from a PFX/P12 file into PEM, the format Apache, Nginx and most Linux tools expect. Upload the PFX above and choose PEM as the target format.

openssl pkcs12 -in certificate.pfx -out certificate.pem -nodes

Convert DER/CER to PEM

Turn a binary DER certificate (often a .cer or .crt file that looks like gibberish in a text editor) into base64 PEM with BEGIN/END headers. Upload the DER file above and choose PEM.

openssl x509 -inform der -in certificate.cer -out certificate.pem

Convert PEM to DER

Convert a text PEM certificate to binary DER, used by Java keystores and some Windows tooling. Upload the PEM file above and choose DER.

openssl x509 -outform der -in certificate.pem -out certificate.der

Convert P7B (PKCS#7) to PEM

Unpack a P7B/PKCS#7 bundle — typically the "certificate with chain" file a CA sends for Windows — into individual PEM certificates. Upload the P7B file above and choose PEM.

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.pem

Convert PEM to P7B (PKCS#7)

Bundle one or more PEM certificates (leaf plus chain) into a single P7B file for import on Windows servers. Upload the PEM certificate above and choose P7B.

openssl crl2pkcs7 -nocrl -certfile certificate.pem -certfile chain.pem -out certificate.p7b

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