What's the difference between PEM and DER?

DER is a binary encoding, while PEM is a text format (-----BEGIN CERTIFICATE-----) that wraps DER in Base64. The content is identical — only the representation differs.

Can I convert private keys too?

Currently only certificate (CERTIFICATE) conversion is supported.

Is the certificate I enter sent to a server?

No. Base64 encoding and decoding happen entirely in your browser.

♻️ SSL Certificate Converter

Convert an SSL certificate between PEM and DER (HEX) formats.

PEM → DER(HEX) DER(HEX) → PEM

Input

Result

How to use

Choose the conversion direction (PEM→DER or DER→PEM).
Enter the certificate content.
Click "Convert" to see the result.

🎯 Use Cases

Register a certificate with systems (like Java) that only support DER
Convert a text-based PEM certificate to binary
Restore a DER certificate from another tool back to PEM

Example

Input

Direction: PEM → DER(HEX)
-----BEGIN CERTIFICATE-----
MIIDDTCCAfWgAwIBAgIUZySY/OCh99ztRItVCcYbaSiR1Ng…
-----END CERTIFICATE-----

Output

30 82 03 0d 30 82 01 f5 a0 03 02 01 02 02 14 67 …

The certificate's Base64 body is decoded and its DER bytes are listed in hex. The leading 30 82 03 0d 30 82 01 f5 is the X.509 certificate's opening ASN.1 SEQUENCE header.

FAQ

What's the difference between PEM and DER?: DER is a binary encoding, while PEM is a text format (-----BEGIN CERTIFICATE-----) that wraps DER in Base64. The content is identical — only the representation differs.
Can I convert private keys too?: Currently only certificate (CERTIFICATE) conversion is supported.
Is the certificate I enter sent to a server?: No. Base64 encoding and decoding happen entirely in your browser.