Pigpen Cipher Decoder & Translator

What Is the Pigpen Cipher?

The pigpen cipher — also called the Freemason’s cipher, the Masonic cipher, or the tic-tac-toe cipher — is a monoalphabetic substitution cipher that swaps each letter for a geometric symbol instead of another letter. The symbols come from drawing the alphabet into two tic-tac-toe grids and two X shapes: each letter’s symbol is simply the “pen” (the surrounding lines) of the slot it lives in, with a dot added for the second grid and second X. Freemasons used it in the 18th century to keep records private, and it still turns up constantly in escape rooms, geocaches, treasure hunts, and puzzle books because it looks mysterious yet is quick to teach.

How to Use This Translator

1. To encode: type in the top box and watch each letter become its pigpen symbol instantly — great for making your own clue.
2. To decode: look at your mystery message one symbol at a time, find the matching key on the symbol keyboard, and tap it. The plain letters build up as you go.
3. Read the chart: the full pigpen alphabet above is the complete key if you’d rather decode by hand.

How the Symbols Are Built

Picture two # grids side by side and two big Xshapes after them. Fill in A–I across the first grid, J–R across the second grid, S–V into the first X, and W–Z into the second X. A letter’s symbol is the shape of the lines that box it in: a corner of the grid gives an L-shaped symbol, an edge gives a U-shape, the centre gives a full square, and an X wedge gives a chevron pointing at the centre. The two dotted sets (J–R and W–Z) use the exact same shapes as A–I and S–V, just with a dot added — which is why the alphabet needs only nine base shapes plus a dot to cover all 26 letters.

Worked Example

Take the word HELLO. H sits on the bottom-middle of the first grid (an upward “U”), E is the centre square, L is bottom-left of the dottedgrid (an L-shape with a dot), and O is bottom-middle of the dotted grid (a dotted “U”). Type HELLO above to see all five symbols line up — then hide the text and try reading them straight off the chart.

Pigpen vs. Other Classroom Ciphers

Pigpen is a substitution cipher just like the Caesar, Atbash, and A1Z26 ciphers — one letter always maps to one fixed symbol. The twist is that the “ciphertext” is drawings rather than letters, so it can’t be typed as ordinary text. If you have a scrambled letter message instead of symbols, our cryptogram solver or cipher identifier is the better starting point.

Frequently Asked Questions

Turn It Into a Printable Puzzle

Building a treasure hunt or classroom activity? Encode your clue here, then use the free cryptogram maker to generate full substitution-cipher worksheets with printable answer keys.