Free Toolkit

PEM/DER ConverterConvert between PEM and DER certificate/key formats.

PEM/DER Converter illustration
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PEM/DER Converter

Convert between PEM and DER certificate/key formats.

How to Use
1

Mode

PEM to DER or DER to PEM.

2

Input

Paste data.

3

Convert

Transform.

What Is PEM/DER Converter?

PEM is Base64 text with headers; DER is raw binary. This tool converts between them. PEM for Apache/Nginx; DER for Java/Windows. All processing client-side.

Why Use Our PEM/DER Converter?

  • Bidirectional
  • Custom labels
  • Certs/keys/CSRs
  • 100% client-side

Common Use Cases

Servers

Convert for servers.

Java

PEM to DER.

Windows

DER for cert stores.

Debug

Inspect DER hex.

Technical Guide

PEM to DER: strip headers, Base64-decode, hex output. DER to PEM: hex to bytes, Base64 in 64-char lines, add headers. RFC 7468.

Tips & Best Practices

  • 1
    PEM = text, DER = binary
  • 2
    Java = DER, Apache = PEM
  • 3
    Label must match content
  • 4
    Use with ASN.1 Decoder

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Frequently Asked Questions

QFree?
Yes.
QDifference?
PEM = Base64 text, DER = binary.
QWhich?
PEM for Linux, DER for Java.
QSafe?
Yes.
QPrivate keys?
Yes.

About PEM/DER Converter

PEM/DER Converter is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.