ROT13 — Free Online Tool

ROT13 cipher rotates A–Z by 13 positions and is commonly used for light obfuscation (spoilers, jokes) and simple puzzles. SWEDevTools: Prism applies ROT13 locally in your browser (no server), and because ROT13 is symmetric, the same operation both encodes and decodes. Paste any text, click Run, and copy the transformed result—or run it again to return to the original. Since SWEDevTools: Prism is local-first and works offline as an installable PWA, you can transform content without sending it to third-party sites. For developer workflows and CTFs, chain ROT13 with Base64, Hex, or Morse tools in a pipeline for fast multi-step decoding. This is especially handy when working through layered encodings step by step.

Features

Frequently Asked Questions

Is ROT13 encryption?

No—ROT13 is trivial to reverse and offers no real security.

How do I decode ROT13?

Run ROT13 again; applying it twice returns the original string.

Does ROT13 change numbers?

No—only A–Z/a–z are transformed.

Why is it used?

It is a simple convention for hiding spoilers or punchlines and appears in puzzles.

Do you upload my text?

No—processing is local.

Is ROT13 a Caesar cipher?

Yes—a Caesar cipher with a fixed rotation of 13.

Can I chain it with Base64?

Yes—pipelines are useful for multi-step transforms.

Can I run offline?

Yes—install the PWA.

What happened to smalldev.tools?

smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.