PEM / DER Converter
Convert certificates, CSRs, public keys, and private keys between PEM, DER, and Base64 without uploading files.
Convert certificate and key files
Certificate encoding
Convert cryptographic objects between text and binary formats
PEM and DER usually contain the same ASN.1 data in different encodings. PEM wraps DER bytes in Base64 text with BEGIN and END labels.
Common conversion workflows
Convert certificates, CSRs, public keys, and private keys from PEM text to DER binary, or convert DER files back into portable PEM and Base64 representations.
Preserve object type
Encoding conversion does not change whether an object is a certificate, request, public key, or private key. Use the correct PEM label and handle private-key output securely.
Guide
About PEM and DER Converter
PEM and DER commonly represent the same ASN.1 object using text and binary encodings.
This tool converts supported certificates, CSRs, and keys between PEM, DER, and Base64 representations.
Changing the encoding does not change the cryptographic object or make private material safe to share.
PEM versus DER
DER is binary ASN.1 data. PEM wraps DER bytes in Base64 with textual labels.
Supported object classes
Conversion can be used for certificates, certificate requests, public keys, and private keys when the object type is recognized.
Correct PEM labels
The output label should match the encoded object, such as CERTIFICATE, CERTIFICATE REQUEST, PUBLIC KEY, or PRIVATE KEY.
Private-key safety
A converted private key remains sensitive regardless of whether it is PEM, DER, or Base64.
FAQ
Frequently asked questions
Does PEM contain different data from DER?
Usually no. PEM commonly wraps the same DER bytes in Base64 text.
Can I convert a certificate from DER to PEM?
Yes, if the input is a supported DER certificate.
Can I convert private keys?
Yes, for supported formats, but the output remains sensitive.
Why is a PEM file larger?
Base64 text and labels add overhead compared with binary DER.
Is Base64 alone the same as PEM?
PEM also includes object-specific BEGIN and END labels and formatting.
Are files uploaded?
Conversion is intended to occur locally in your browser.
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