Ciphers & Decoders
Decode classic ciphers — Caesar, ROT13, Vigenère, Atbash and more.
Caesar Cipher Decoder
Try all 25 shifts at once — we highlight the one that reads as real words.
LiveROT13 Decoder
Decode ROT13 text instantly — the internet's classic spoiler code.
LiveVigenère Cipher Decoder
Decode Vigenère messages with a keyword, plus key-length help.
LiveAtbash Cipher Decoder
Flip the alphabet: A becomes Z, B becomes Y. Decode in one click.
Tap Code Decoder
Decode tap-code knocks from the classic 5×5 Polybius grid.
Cipher Identifier
Paste unknown ciphertext — we guess which cipher made it.
Rail Fence Cipher
Read zig-zag transposition ciphers with any number of rails.
Playfair Cipher
Decode digraph ciphers from the 5×5 keyword square.
Four-Square Cipher
Decode digraph ciphers built from four 5×5 squares.
Straddling Checkerboard
Letters to digits with the spy cipher used in the VIC system.
Hill Cipher Decoder
Matrix cipher decoding with 2×2 and 3×3 keys.
Chaocipher
Two-disk cipher with alphabets that change after every letter.
Quagmire Cipher
Vigenère with mixed alphabets — Quagmire I to IV.
XOR Cipher Decoder
Brute-force single-byte XOR and crack repeating-key XOR.
Letters, Numbers & Codes
Turn letters into numbers, numbers into letters, and crack keypad codes.
Letters to Numbers Converter
Turn any word into numbers: A=1, B=2 … Z=26. Fast, free, with copy button.
LiveNumbers to Letters Converter
Turn 8-5-12-12-15 back into HELLO. The reverse of the tool above.
A1Z26 Cipher
The classic A=1, Z=26 letter-number code, encode and decode.
Polybius Square Cipher
Letters to coordinate pairs from the 5×5 grid.
Phone Keypad Decoder (T9)
Decode old-phone keypad numbers — T9 and multi-tap.
Keyboard Shift Cipher Decoder
Fix text typed one key to the left or right on a QWERTY keyboard.
Leet Speak Translator
Convert text to 1337 5p34k and back.
Alphabets & Symbols
Translate between alphabets and symbol systems.
Morse Code Translator
Dots and dashes to text and back, with sound.
Braille Alphabet Translator
Text to Braille dot patterns and back.
Semaphore Flags Translator
Flag positions to letters — the naval signal alphabet.
Dancing Men Cipher
Sherlock Holmes' stick-figure code, decoded.
Elder Futhark Runes Translator
Text to Viking runes and back.
Pig Latin Translator
English to Pig Latin and back — ellohay!
Code-Breaking Helpers
Analysis tools that help you identify and crack unknown ciphers.
Index of Coincidence Calculator
Measure letter patterns to guess the cipher family.
Kasiski Examination
Find repeated patterns to guess a Vigenère key length.
Audio Spectrogram
See hidden pictures inside audio files.
No tool matches your search yet. Try “caesar”, “numbers” or “morse”.
About these tools
Every tool on this site works 100% in your browser. Your text never leaves your device — nothing is uploaded to a server. That makes the tools fast, private, and free to use without an account.
The tools cover classic ciphers (Caesar, Vigenère, Atbash, ROT13), letter-and-number codes (A1Z26, letters to numbers), and code-breaking helpers (cipher identifier, frequency tools). Each tool page explains how the cipher works with a worked example, so students, puzzle fans, geocachers, escape-room players and CTF beginners can learn while they decode.
One honest note: classical ciphers are puzzles and history, not real security. Never use them to protect private information — modern encryption exists for that job.