Paste one or multiple PEM blocks — certificates, private keys, CSRs, or chains.
Ready to format
Paste a PEM block and click Format PEM// normalize line breaks and block wrappers for pem files
Format, validate, and normalize PEM certificates, private keys, and certificate chains. Fix line breaks, block wrappers, and encoding issues instantly in your browser.
Paste one or multiple PEM blocks — certificates, private keys, CSRs, or chains.
Ready to format
Paste a PEM block and click Format PEMPaste one or multiple PEM blocks into the text area — certificates, private keys, CSRs, or full certificate chains.
Select formatted (standard 64-char line wrap), single line, or raw base64 body only.
Click Format PEM. Each block is normalized and labeled. Copy individual blocks or all at once.
PEM (Privacy Enhanced Mail) is the most common format for SSL/TLS certificates, private keys, and certificate chains. It uses Base64-encoded DER data wrapped in -----BEGIN ... ----- header and footer lines.
This tool normalizes any broken, malformed, or single-line PEM data back to the RFC 7468 standard: 64-character line wrapping with proper headers and footers.
PEM stands for Privacy Enhanced Mail. It's a Base64-encoded format for storing cryptographic objects like X.509 certificates, private keys, and certificate signing requests (CSRs). PEM files are identified by their -----BEGIN...----- and -----END...----- header lines.
PEM corruption usually happens when files are copied through email clients, chat apps, or terminals that re-wrap text. Sometimes the Base64 body gets merged into a single line, or newlines are replaced with spaces or other characters. This tool detects and fixes all of these issues.
According to RFC 7468, PEM Base64 data must be wrapped at 64 characters per line. Some older implementations use 76 characters, but 64 is the modern standard used by OpenSSL, Nginx, Apache, and most TLS libraries.
Yes! Paste the entire chain (root CA + intermediates + server certificate) and the tool will split and format each block individually. Each block is labeled and can be copied separately or all together.
Yes. All processing happens entirely in your browser using JavaScript and PHP server-side — your data is never stored, logged, or sent to any third party. You can also inspect the source code directly in your browser's developer tools.
This tool supports all standard PEM block types including CERTIFICATE, PRIVATE KEY, RSA PRIVATE KEY, EC PRIVATE KEY, PUBLIC KEY, CERTIFICATE REQUEST, NEW CERTIFICATE REQUEST, DH PARAMETERS, CERTIFICATE REVOCATION LIST, and more.
PEM is Base64-encoded DER with ASCII headers — human-readable. DER is the raw binary format. PFX (also called PKCS#12) is a binary archive that can bundle the certificate and private key together. This tool handles PEM format only.
After formatting, you can verify a certificate with: openssl x509 -in cert.pem -noout -text. For private keys: openssl rsa -in key.pem -check. For CSRs: openssl req -in csr.pem -noout -verify.
PEM (Privacy Enhanced Mail) is the de facto standard encoding format for SSL/TLS certificates, private keys, certificate signing requests (CSRs), and certificate revocation lists (CRLs). Despite its name, PEM has nothing to do with email — it was originally designed for secure mail exchange in the 1990s, but the format stuck around and became ubiquitous in the world of public key infrastructure (PKI).
A properly formatted PEM file follows a strict structure: a -----BEGIN TYPE----- header line, the DER-encoded cryptographic data converted to Base64 and wrapped at exactly 64 characters per line, followed by a -----END TYPE----- footer. When this structure breaks — which happens frequently when PEM data is copy-pasted across chat apps, emails, CI/CD environment variables, or documentation — the result is a certificate or key that OpenSSL and most TLS libraries will simply refuse to parse.
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PEM corruption is surprisingly common in real-world workflows. Here are the most frequent causes developers encounter:
SSL_CERT typically strips all newlines, resulting in a single continuous Base64 string.\r\n (CRLF) while Linux tools expect \n (LF). Mixing these causes silent parse failures.=) are stripped or corrupted, making the data undecodable.The PEM Formatter tool normalizes malformed PEM data through a series of steps:
-----BEGIN ... ----- and -----END ... ----- marker pairs, supporting every standard PEM block type.A-Z, a-z, 0-9, +, /, =). Any invalid characters are flagged with a clear error message.The -----BEGIN TYPE----- header identifies the cryptographic object contained in the PEM block. Understanding these types helps you verify you have the right data for your use case:
A certificate chain (also called a bundle or CA bundle) is a PEM file containing multiple concatenated certificate blocks. A typical chain includes the server certificate, one or more intermediate CA certificates, and optionally the root CA certificate. Web servers like Nginx and Apache accept these bundles directly as the ssl_certificate or SSLCertificateChainFile directive.
This PEM Formatter automatically detects multiple blocks in your input and splits them for individual inspection. You can see each block's type, line count, and byte size, then copy them individually or all together in the correct chain order.
While PEM is the most human-friendly format, there are cases where other encodings are required. DER is the raw binary encoding of the same data — smaller in size but not human-readable or copy-pasteable. It's commonly used in Java environments and some older middleware. PFX / PKCS#12 is a binary archive format that bundles the certificate and private key together, password-protected. It's the standard on Windows and commonly used for importing/exporting certificates in IIS and Azure. This tool handles PEM only; use OpenSSL to convert between formats with openssl pkcs12 or openssl x509 -outform der.
One of the most common real-world PEM problems occurs when teams store certificates or private keys in environment variables for Docker, Kubernetes, GitHub Actions, or other CI/CD systems. Most systems strip newlines from env var values, converting a properly formatted multi-line PEM into a single broken string.
The solution is to either store the Base64-encoded single-line version and decode it at runtime, or use the newline escape sequence (\n) as a placeholder. This tool's "single line" output mode is ideal for generating the compact form you need for env vars — just wrap it back when needed.
After formatting, you should always verify the result with OpenSSL before deploying. Here are the essential commands:
openssl x509 -in cert.pem -noout -text — Parse and display a certificate's detailsopenssl rsa -in key.pem -check — Verify RSA private key integrityopenssl req -in csr.pem -noout -verify — Verify a CSR's signatureopenssl verify -CAfile chain.pem cert.pem — Verify a certificate against a CA chainopenssl s_client -connect example.com:443 -showcerts — Retrieve and display a server's certificate chain