SSL Converter
Convert SSL certificates between PEM, DER, PFX/P12, and P7B/PKCS7 formats for Apache, Nginx, IIS, Tomcat, and more.
100% Free
PEM / DER / PFX / P7B
All Major Servers
Convert SSL Certificate Format
SSL Certificate Formats & Server Compatibility
| Format | Extension | Best For | Server |
|---|---|---|---|
| PEM | .pem, .crt, .cer | Apache, Nginx, Linux | Most common |
| DER | .der, .cer | Java applications | Binary format |
| PFX/P12 | .pfx, .p12 | IIS, Windows, Azure | Includes private key |
| P7B/PKCS7 | .p7b | Tomcat, Java Keystore | Chain only, no private key |
4 FormatsPEM, DER, PFX, P7B
All ServersApache, Nginx, IIS, Tomcat
Nothing StoredCerts never logged
InstantConvert in milliseconds
About SSL Converter
The SSL Converter is a free online tool that converts SSL/TLS certificate files between different formats including PEM, DER, PFX/P12 and CRT/CER. Different web servers, applications and hosting environments require SSL certificates in specific formats — for example, Apache uses PEM format while Windows IIS uses PFX format. This tool handles the conversion without requiring command-line OpenSSL access.
Supported Format Conversions
- PEM to DER — Convert Base64-encoded PEM to binary DER format
- DER to PEM — Convert binary DER to Base64 PEM format
- PEM to PFX/P12 — Bundle certificate + private key for Windows/IIS
- PFX to PEM — Extract certificate and key from a PFX bundle
- CER/CRT to PEM — Convert various certificate file extensions to PEM
How to Convert SSL Certificates
- Select the source format and target format
- Upload your certificate file or paste the PEM content
- For PFX conversions, provide the password if the file is password-protected
- Click Convert
- Download the converted certificate file
When You Need SSL Conversion
- Migrating from Apache (PEM) to IIS (PFX) or vice versa
- Installing an SSL certificate on a platform that requires a specific format
- Extracting individual certificate and key components from a PFX bundle
Free, no login required. Handle private keys with care — never share them.
Want to learn more? Read our complete guide: What is SSL and Does HTTPS Affect Google Rankings? →
Frequently Asked Questions
What SSL format does my server need?
Apache and Nginx use PEM (.crt / .pem). IIS and Windows servers use PFX/P12 (contains cert + key). Java and Tomcat use P7B or JKS. DER is a binary version of PEM. When in doubt, PEM works everywhere with the right conversion.
What is the difference between PEM and DER?
PEM and DER contain the same certificate data — DER is binary, PEM is the same data Base64-encoded with header/footer lines. PEM is human-readable in a text editor; DER is not. Most Linux servers use PEM.
Do I need my private key to convert?
Only when converting to PFX/P12 format, which bundles the certificate and private key together. PEM, DER, and P7B conversions only require the certificate itself. The CA bundle (chain) is optional but recommended for including intermediate certificates.
What is a CA bundle?
A CA bundle (or chain file) contains the intermediate and root certificates from your Certificate Authority. Including it ensures browsers can trace the full trust chain from your server certificate back to a trusted root CA, preventing chain errors.