Compare
PEM vs PFX
PEM is a text encoding for certificate-related structures; PFX/P12 is a PKCS#12 container that can package certificates and private keys.
Which format should you choose?
Use the format required by the receiving service. Treat any file that may contain a private key as a secret.
Good fit for PEM
Represent certificates and keys as text
- Systems requesting PEM-encoded material
Good fit for PFX
Certificate migration
- Importing a certificate identity into a trusted system that requires PKCS#12
Basic information
| Field | PEM | PFX |
|---|---|---|
| Extension | .pem | .pfx, .p12 |
| MIME type | application/x-pem-file | application/pkcs12 |
| Common uses | Represent certificates and keys as text | Certificate migration |
| How to open | Inspect the labels as text without pasting the contents into public chats or shared locations. | Open only in a trusted certificate manager and verify its contents. |
| Export or convert | Before converting to DER or PKCS#12, identify the contained objects and whether a private key must be handled. | When exporting to PEM, check whether a private key is included and protect every output file. |
Choose by use case
Systems requesting PEM-encoded material
Represent certificates and keys as text
PEMImporting a certificate identity into a trusted system that requires PKCS#12
Certificate migration
PFXKey point 1
PEM files are text with labels and may contain different structures.
More on the differencesKey point 2
PFX/P12 is a container that can bundle certificates and keys.
More on the differencesMore on the differences
Before conversion, identify the contents and confirm the target application's requirements. Protect private keys and passwords separately.
- A .pem extension alone does not identify whether the content is a certificate or key.
- PFX/P12 containers may be password-protected but still require secure storage and transfer.
Frequently asked questions
Does PEM always contain a private key?
No. PEM can encode certificates, public keys, private keys, or other structures. Check its labels and handle it cautiously.
Is a PEM file always a certificate?
No. PEM can encode certificates, private keys, public keys, or signing requests. Inspect its labels and validate the object.