SSL & Certificates

PEM to DER Converter

Convert a Base64 PEM certificate, request or key into the binary DER form.

PEM certificate
Output

Result appears here after you select

{ } How to use

  1. Paste the PEM block, including its BEGIN and END lines.
  2. Select Process.
  3. Download the .der file.

{ } How it works

PEM to DER Converter works on the text you provide. Select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Input

  • PEM certificate — paste or type your input in the left panel (use Sample for an example)

Output

DER text — copy or download it from the Output panel.

{ } Common uses

  • Prepare a certificate for a Java keystore or a device that only accepts DER.
  • Convert a certificate for a system that rejects the Base64 form.

{ } Limitations

  • DER holds one object. Paste a chain and only the first block is converted — the others are reported but left out.
  • The conversion is only the encoding: the certificate itself is unchanged, so a DER file is exactly as sensitive as the PEM it came from.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

This tool works on one input at a time.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

What is the difference between PEM and DER?

None, as far as the certificate is concerned. DER is the raw binary; PEM is that same binary in Base64 between two labelled lines so it survives being pasted into an email. Converting between them changes the packaging, never the contents.

Is my private key uploaded anywhere?

No. Every one of these tools runs entirely in your browser — the certificate and key are read, converted and shown without a byte being sent anywhere. That is what makes it safe to paste a private key, which you should never do on a site that converts it on a server.

Does this work with ECDSA certificates?

Yes. RSA, ECDSA and Ed25519 are all read the same way, because the structure is read directly rather than through a library that only understands RSA keys.