CRACK THE CODE
A secret message. Yours to solve.
Turn a sentence into a printable secret code.
A4 worksheet + separate answer key. PNG downloads the current preview.
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Backup includes all saved puzzles and collections, across every puzzle type. Unsaved drafts and book setup are not included.
A home for your favourite puzzles
Create a puzzle above, then save it here for your next lesson.
Make a message worth decoding.
01Enter a message and choose difficulty.
02Generate your secret code.
03Save, print or download.
How does the code work?
Each English letter is replaced by one different letter. The same letter always uses the same code throughout the message. Spaces, numbers and punctuation stay unchanged.
What changes with difficulty?
Easy reveals up to five letter mappings; Medium reveals up to two; Hard reveals none. Hints are filled in throughout the worksheet. At least one unique letter remains hidden, so short messages may have fewer hints.
Can I use my own message?
Yes. Add up to 240 characters using English letters, numbers and standard punctuation. Letters become uppercase. New lines and repeated spaces become single spaces.
Where are the answers?
Switch on Answer key to reveal the decoded letters. PDF and Print include a worksheet and a separate answer key. PNG exports the current preview.
Can I save the exact code?
Save current puzzle keeps the message, code and difficulty in this browser on this device. Open it again from My puzzles. Clearing browser data removes saved puzzles.
Can I solve it on screen?
This is a printable worksheet maker. Download or print the puzzle to fill in your answers.