Transposition Cipher Decoder
Input
Results
Don't know the shift? This tries all 25 possible shifts on your input text above so you can spot the plaintext by eye.
About This Cipher Decoder
A transposition cipher (also called a shift cipher) is a method of encoding and decoding a string where letters are shifted a set number of places in the alphabet. For example, in the famous Caesar Cipher all letters are shifted 3 to the right to encode and 3 to the left to decode. This decoder takes that a step farther and lets you choose how many letters to shift. You can choose any number between -20 and 20. Anything positive is encoding and anything negative is decoding. For example a string encoded using a shift of 5 can be decoded with a shift of -5. Using a shift of 0 will just give you the same string back.
If you have encoded (ciphertext) text but don't know what shift was used, use the Decode All Shifts button above — it runs the ciphertext through all 25 possible shifts at once so you can scan the results and spot the readable plaintext.
How This Decoder Handles Text
A couple of notes on how this particular decoder works.
First, it keeps lower cased letters lower cased and upper cased letters upper cased. Anything other than a letter is kept as is. So a shifted ! will stay ! no matter what shift value you use.
And if the shift takes a letter past the end of the alphabet, it wraps around to the beginning. So a shift of 7 on X will give you E. Negative shifts work the same way if they take a letter past the beginning of the alphabet. So a shift of -7 on E will give you X.
Frequently Asked Questions
What is a cipher decoder? A cipher decoder reverses an encoding process to reveal the original message. This tool decodes shift-based (transposition) ciphers, including the classic Caesar cipher, by shifting each letter backward by a chosen amount.
How do I decode a message if I don't know the shift? Paste the ciphertext into the input box and click Decode All Shifts. The tool tries all 25 possible shift values and lists every result, so you can quickly spot the one that reads as plain English.
Is this the same as a Caesar cipher decoder? Yes — a Caesar cipher is a transposition/shift cipher with a fixed shift of 3. This tool works the same way but lets you use any shift from -20 to 20, so it covers Caesar ciphers and any other single-shift cipher.
Does this decoder work on numbers or punctuation? No — only letters (A–Z, a–z) are shifted. Numbers, spaces, and punctuation are left unchanged, which keeps the message's structure and word breaks intact.
Is my text sent anywhere? No. All encoding and decoding happens locally in your browser with JavaScript — nothing you type is uploaded or stored.
