Certificate Format Converter

A Certificate Format Converter is a tool that transforms SSL/TLS certificates and keys between different encoding formats. Certificates are used to establish secure encrypted connections (HTTPS) and verify the identity of websites, servers, and applications. Different platforms and software require certificates in different formats.

The three main certificate formats are:

• PEM (Privacy Enhanced Mail) — The most common format, using Base64-encoded ASCII text with -----BEGIN CERTIFICATE----- headers and footers. Used by Apache, Nginx, cURL, OpenSSL, and most Unix/Linux systems. File extensions: .pem, .crt, .cer, .key.
• DER (Distinguished Encoding Rules) — A binary format using raw ASN.1 encoding. Used by Java platforms, Windows, and some embedded systems. File extensions: .der, .cer.
• PFX / PKCS#12 — An archive format that bundles the certificate, private key, and intermediate certificates into a single encrypted file. Used by Microsoft IIS, Windows, and for certificate import/export. File extensions: .pfx, .p12.

1. Paste or upload — Paste your certificate data into the text area, or click "Upload File" to select a .pem, .der, .crt, .pfx, or .key file. You can also click "Load PEM Sample" or "Load DER Sample" to try with sample data.
2. Select output format — Choose PEM, DER, or PFX/PKCS#12 from the dropdown menu. For PFX output, an optional passphrase field will appear.
3. Click Convert — The tool converts your certificate to the selected format. Certificate details will be displayed if a valid X.509 certificate is detected.
4. Copy or download — Use the Copy button to copy the output to your clipboard, or click Download to save it as a file.