ROT13 / Caesar Cipher
Encode and decode with ROT13, ROT5, ROT18, ROT47 or an arbitrary Caesar shift. Live, with an all-shifts brute-force panel for cracking unknown rotations.
About this ToolHow it works, benefits & use casesTap to collapse
ROT13 is the classic letter-rotation cipher, and this tool covers the whole rotation family in one place. Pick ROT13 to shift A–Z and a–z by 13 (case preserved, digits and punctuation untouched), ROT5 to rotate digits 0–9 by 5, ROT18 to do both at once, or ROT47 to rotate the full printable-ASCII range 33–126 by 47 so punctuation and symbols are scrambled too. All four are self-inverse — applying the same mode again restores the original — so there is no separate decode step. Choose Caesar mode to shift letters by any value from 1 to 25 with explicit Encode/Decode direction. The most useful feature for cracking unknown text is the all-shifts panel: it lists every Caesar rotation (0–25) of your input at once and highlights the row matching the active shift, so you can eye-scan for the readable line. Conversion is live, with a swap button and a shareable URL, and runs entirely in your browser.
How to Use
- 1In the Cipher card, choose a Mode: ROT13, ROT5, ROT18, ROT47, or Caesar.
- 2For Caesar, enter a Shift from 1 to 25 and pick Encode or Decode direction.
- 3Type or paste your text into the input — the rotated output updates live.
- 4Scan the "All Caesar shifts" panel to brute-force an unknown rotation; the active shift row is highlighted.
- 5Click "Apply cipher" to confirm, then copy, download, swap input ↔ output, or share the link.
Key Benefits
- Five modes in one tool: ROT13, ROT5, ROT18, ROT47, and arbitrary Caesar
- ROT13/5/18/47 are self-inverse — apply again to decode, no direction needed
- ROT47 rotates all printable ASCII so symbols and punctuation are scrambled too
- Caesar mode supports any 1–25 shift with explicit Encode/Decode
- All-shifts brute-force panel shows every rotation 0–25 and highlights the active one
- Case-preserving letter rotation that leaves other characters untouched
- Live conversion with swap and a shareable URL, all in-browser
Common Use Cases
- Hiding spoilers, puzzle answers, or punchlines with ROT13
- Decoding ROT13 text pasted from a forum, README, or Usenet-style post
- Cracking an unknown Caesar shift by scanning the all-shifts panel
- Demonstrating substitution ciphers when teaching basic cryptography
- Lightly obfuscating digits or symbols with ROT5 or ROT47
Cipher
Shift A–Z/a–z by 13. Self-inverse: apply twice to restore.
0 characters · live
Shift A–Z/a–z by 13. Self-inverse: apply twice to restore.
Enter text above to see the rotated result.
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Related tools
ROT13 rotates only letters by 13. ROT5 rotates only digits 0–9 by 5. ROT18 combines them — ROT13 on letters and ROT5 on digits. ROT47 is broader, rotating every printable ASCII character (codes 33–126) by 47, so punctuation and symbols are also scrambled. All four are self-inverse, meaning running the same mode a second time gives back the original text.
Because ROT13 is its own inverse: shifting 13 places and then another 13 returns to the start of the 26-letter alphabet. The same is true of ROT5, ROT18, and ROT47. Only Caesar mode, which can use any shift from 1 to 25, needs an explicit direction — decoding there applies the complementary 26 minus the shift.