ROT Encoder/Decoder - ROT13 Cipher

Free online ROT encoder and decoder tool with support for ROT-0 to ROT-25. Encode and decode text using ROT-13 cipher (Caesar cipher). Simple letter substitution cipher for basic text obfuscation. Perfect for puzzles, CTF challenges, and learning cryptography basics.

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ROT-13 is symmetric (encode = decode). Other ROTs decode by reversing shift.

ROT Encoder/Decoder - ROT-13 and Caesar Cipher Online

A free online ROT encoder and decoder tool that supports ROT-0 through ROT-25. Apply the classic ROT-13 cipher or any Caesar cipher shift to encode text, or decode ROT-encrypted messages. Simple letter substitution cipher commonly used in puzzles, CTF challenges, and basic cryptography education.

What is ROT cipher?

ROT (rotate) is a simple letter substitution cipher where each letter is replaced by another letter a fixed number of positions down the alphabet. ROT-13 is the most famous, rotating letters by 13 positions.

Example (ROT-13):
A → N, B → O, ..., M → Z, N → A, ..., Z → M
"HELLO" → "URYYB"

ROT-13 is symmetric: encoding twice gives original text.

How do I use ROT cipher?

1. Select mode (Encode or Decode)
2. Enter your text
3. Choose ROT number (0-25, default 13)
4. Click Process

ROT-13 is special: encode = decode
Other ROTs: decode reverses the shift

Example:
Text: "HELLO"
ROT-13: "URYYB"
ROT-13 again: "HELLO" (back to original)

Is ROT cipher secure?

NO! ROT cipher provides NO security.

✗ Only 26 possible keys
✗ Easily broken by brute force
✗ Pattern analysis reveals text
✗ Not for real encryption

✓ Good for:
- Puzzles and games
- CTF challenges
- Learning cryptography
- Basic text obfuscation
- Hiding spoilers

✗ Never use for:
- Password protection
- Sensitive data
- Security purposes

What's the difference between ROT-13 and other ROTs?

ROT-13 (shift by 13):
✓ Symmetric: encode = decode
✓ Classic and well-known
✓ A ↔ N, B ↔ O, etc.

Other ROTs (shift by 1-25):
- Different shift amounts
- Encode and decode are different
- ROT-N decode = ROT-(26-N) encode

ROT-0: No change
ROT-25: Reverse of ROT-1
ROT-13: Special (symmetric)

Key Features

  • Encode text with ROT cipher instantly
  • Decode ROT-encrypted text
  • Support for ROT-0 through ROT-25
  • ROT-13 classic cipher included
  • Preserves non-alphabetic characters
  • Case-sensitive transformation
  • Swap between encode and decode modes
  • Copy results to clipboard
  • Dark mode support
  • 100% client-side processing
  • Works offline
  • No registration required
See also
ENCODING
WUTOOLS