Morse Code Audio Decoder

You have a recording with morse code in it — a practice file, a puzzle, a hidden message in a song, a radio catch — and you need the text. Play it here. This decoder listens for the tone, measures every dot and dash, rebuilds the message, and estimates the sending speed. Everything runs locally in your browser: no uploads, no accounts, no waiting.

How machine decoding works (and why it's harder than it sounds)

To your ear, morse is obvious: beep-beeeep-beep. To software, a recording is just a wall of numbers. The decoder's job is a chain of small judgments, each of which can go wrong in the field:

1. Energy tracking. The signal is sliced into 20-millisecond windows and each window's loudness measured, producing a loudness contour over time.
2. Adaptive thresholding. Background noise constantly shifts the floor, so the decision line between "tone" and "silence" is computed from the recording's own quietest and loudest quartiles — this is what the sensitivity slider moves.
3. Symbol classification. Every tone segment is compared to the shortest one heard: roughly one unit = dot, three units = dash. On real hand-sent code, dashes wobble between 2.5 and 4 units, which is exactly where naive decoders fall over.
4. Gap interpretation. Silence carries the grammar: one unit between symbols, three between letters, seven between words. Fat-fingered spacing is the #1 cause of run-on "words" in decoded output.

That's also why humans still beat software on poor signals: your ear does step 1–2 natively and your brain is stubborn about context. The listening drills in our practice games train exactly that machine-beating skill.

Getting the best results

• Isolate the morse section. If the recording has speech or music before the tones, trim to the signal — the adaptive threshold thanks you.
• Start sensitivity at 50%. Missing characters? Raise it. Getting garbage from silence? Lower it.
• Verify against the pattern. The decoder shows the raw dot-dash pattern above the text — when the text looks wrong, the pattern is usually readable by eye against the chart.
• Test the loop yourself. Generate a WAV from the translator, feed it back here, and watch round-tripping confirm both tools at once.

Who uses audio decoding?

Amateur radio operators log reverse-beacon spots and verify their own fist by recording and decoding. Puzzle designers hide audio morse in escape rooms and ARGs, and solvers use tools like this one to extract it. Teachers check whether a student's sent code is actually readable. And every few weeks someone discovers a morse easter egg in a film score or game soundtrack and wants to know what it says — usually SOS, sometimes something better.

Frequently asked questions