Online Tool Store
Semaphore Flag Translator
Convert text to flag semaphore positions and back, with the clock-face notation and the control signals the system actually uses.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Education
Semaphore Flag Translator
Frontend preview — no upload or external service.
Semaphore output
HELP: H = flags at low-left and low-right, E = low-left and high-right, L = low-left and up-right, P = up-left and low-right — using clock positions from the signaller's view.
How the Semaphore Flag Translator works
- Enter the text; semaphore covers letters and numerals, not punctuation.
- Read positions as clock angles from the signaller's own perspective, not the observer's.
- Note the numeric sign — numbers reuse letter positions and need a control signal to switch mode.
The method
Each letter is a pair of flag positions on a 45-degree clock face, giving enough distinct combinations for the alphabet plus control signals.
two arms x 8 positions, minus impossible overlaps, covers 26 letters plus numerals and controls
Numerals A to K double as digits 1 to 0, distinguished only by the preceding numeric sign — which is why a missed control signal garbles a whole number.
FAQ
Is semaphore still used?
Rarely, and mostly as a backup where radio silence matters or equipment has failed. Navies still teach it, and it appears in scouting and maritime training.
Why do numbers reuse letter positions?
Because there are only so many distinguishable arm positions. A numeric sign switches the receiver into number mode and a letters sign switches back, which is why control signals matter as much as the characters.
Whose left is left?
The signaller's. Positions are described from the sender's point of view, which means an observer sees them mirrored — a reliable source of confusion when learning.
How we compare
| Feature | Online Tool Store | Pen and paper | A classroom platform |
|---|---|---|---|
| Both translation directions | ✓ | One way | Yes |
| Control signals explained | ✓ | ✗ | Sometimes |
| No account | ✓ | ✓ | ✗ |
| Works offline once loaded | ✓ | ✓ | ✗ |
Semaphore Flag Translator uses the signaller's perspective and shows the control signals, which is where beginners most often garble a message.