CER to PEM converter
To convert CER to PEM, drop your CER file in the box below. It converts straight away; press Download to save the PEM. It all happens in your browser, so your file stays on your device.
Convert to
Converted on this device, never uploaded
What changes
| CER to PEM | What happens |
|---|---|
| DER .cer | Written as PEM |
| Base-64 .cer | Windows’ other export choice: already PEM inside, written again cleanly |
| Also | A text summary of the certificate |
| Facts | Open the file in the viewer to see names, dates and fingerprints before you convert |
How to convert CER to PEM
- Add your CER. Drop the file in the box, or click to choose it. It becomes PEM straight away.
- Check the result. Look at the preview and the size. The defaults are right for most files.
- Download. Press Download to save the PEM.
Why PEM
Windows exports certificates as .cer, usually binary DER; Linux servers and OpenSSL want PEM text.
Questions
The certificate export wizard offers DER or Base-64. Both convert here.
No. PEM and DER are two wrappings of the same bytes: the fingerprints, signature and dates stay exactly the same.
No. The file is read and converted in your browser, so it stays on your device.
No. The conversion happens right in your browser, so your file stays on your device. There is no account to make, either.