{ } How to use

Paste the certificates, one PEM block after another.
Choose binary or Base64 output.
Select Process, then download the .p7b.

{ } How it works

PEM to P7B Converter works on the text you provide. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Inputs

PEM certificates — paste or type your input in the left panel (use Sample for an example)
Output format — choose one — Binary (.p7b), Base64 (BEGIN PKCS7) (default: Binary (.p7b))

Output

P7B text — copy or download it from the Output panel.

{ } Common uses

Give Windows or a Java tool the single chain file it expects.
Collect a leaf certificate and its intermediates into one file to hand on.

{ } Limitations

Only certificates go in. A private key cannot be carried in a .p7b — use PEM to PFX for that.
The file carries no signature; it is a plain container for certificates.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

This tool works on one input at a time.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

Is my private key uploaded anywhere?

No. Every one of these tools runs entirely in your browser — the certificate and key are read, converted and shown without a byte being sent anywhere. That is what makes it safe to paste a private key, which you should never do on a site that converts it on a server.

Does this work with ECDSA certificates?

Yes. RSA, ECDSA and Ed25519 are all read the same way, because the structure is read directly rather than through a library that only understands RSA keys.