Pigpen Cipher Translator

The pigpen cipher swaps each letter for a geometric symbol — a fragment of a grid line, sometimes with a dot added — rather than for another letter or a sound. That makes it fundamentally different from every other converter on this site: Morse, NATO, braille, binary and Caesar all substitute one kind of text-representable symbol for another, which a simple lookup-and-swap tool handles cleanly. Pigpen symbols are shapes, not characters, so the converter above renders each one as real drawn geometry — SVG lines and a center dot, not a font character standing in for a corner-bracket or a dotted triangle. What follows explains exactly how those shapes are built, so you can also encode and decode pigpen entirely by hand.

The Four Grids That Cover 26 Letters

The version most commonly taught today uses four separate grids, each grid's shape supplying the outline of a symbol and each letter's position inside that grid supplying which fragment of the outline gets used. Two of the grids are 3x3 tic-tac-toe grids (nine cells each, so eighteen letters between the pair), and two are large X shapes made from two crossed lines (four cells each, so eight letters between the pair) — eighteen plus eight covers the full 26-letter alphabet exactly.

• Grid 1 (plain tic-tac-toe): letters A through I, filled left to right, top to bottom.
• Grid 2 (dotted tic-tac-toe, same layout as Grid 1): letters J through R, each symbol identical in outline to its Grid 1 counterpart but with a dot added.
• Grid 3 (plain X / crossed lines): letters S, T, U, V, filling the four wedges.
• Grid 4 (dotted X, same layout as Grid 3): letters W, X, Y, Z, again matching Grid 3's shapes with a dot added.

How to Encode a Letter by Hand

Find which of the four grids the letter falls in, then draw only the lines of that grid's cell that actually border the letter's position — not the whole grid, just the lines touching that specific cell. How many lines a symbol keeps runs opposite to what most people guess at first: a corner letter like A only touches two of the grid's interior lines, so its symbol is the smallest thing the system produces, a simple two-line bracket. A letter on the middle of an edge, like B or H, touches three lines and reads as a wider, U-shaped bracket. The letter sitting in the dead center of a tic-tac-toe grid — E in Grid 1, N in Grid 2 — is the one exception to the bracket pattern, and it's bordered on all four sides at once, not on none of them: its symbol is a complete closed square, and in the dotted grid that's a full square with a dot in the middle, never a lone dot standing on its own. This is the part a text-only converter genuinely can't do — it requires drawing a shape, not selecting a character.

A Worked Example, by Hand: "HI"

H sits in the bottom-middle cell of Grid 1 (plain tic-tac-toe), bordered by lines on its left, right and top — so its symbol is a squared-off U shape, open at the bottom rather than the top. I sits in the bottom-right corner of the same grid, bordered only on two sides (left and top), producing a compact backwards-L bracket that opens toward the bottom-right instead. Sketching both on paper next to each other is a fast way to check your understanding of the grid-position rule before trying a longer message.

Where Pigpen Actually Comes From

Records of grid-based substitution ciphers resembling pigpen go back at least to the 18th century, and the specific four-grid version described above is most closely associated with English Freemasonry — it's genuinely the reason the cipher is also widely called the Freemason's cipher — though the underlying idea of hiding letters inside geometric fragments has been claimed, with varying degrees of documentation, by earlier groups including the Rosicrucians and, in some popular accounts, the Knights Templar. It was never meant to be unbreakable; a substitution cipher with a fixed, discoverable symbol set is vulnerable to the same frequency-analysis techniques that crack a Caesar cipher, and it was used historically more for casual concealment among initiates than for genuine military secrecy.

Reading the Result Above

Type a word into the converter and each letter renders as its real symbol, drawn live; the full A-Z key below the result shows every symbol at once, so you can check a letter you're unsure of without leaving the page. Pigpen has no symbols for digits or punctuation — any character outside A-Z passes through as plain text in a dashed box, rather than being silently dropped, so you can see exactly what wasn't covered. To practice encoding by hand, draw the four grids on paper, write your message's letters into their grid positions in pencil first to confirm placement, and only then trace the bordering lines into symbols.