Morse Code Audio Decoder
Have an audio clip full of beeps? This free tool listens to it and writes out the message, showing the dots, dashes, speed and pitch as it goes.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.
What it does
The Morse Code Audio Decoder on Unscramble Words 4U has two tabs. Upload audio reads a recording you choose from your device; Listen (microphone) decodes Morse playing near your computer or phone in real time. For files, it looks for the strongest beeping tone, measures each beep and silence, and produces the decoded text with timestamps. You also get a spectrogram, a waveform and a timing strip, plus an estimate of the sending speed (wpm) and the pitch in hertz.
If the result looks wrong, you can change the sensitivity, enter the tone yourself or pick a speed, and it decodes the file again instantly. Clicking a word or the waveform plays that part of the recording. A built-in sample, with an option to add noise, lets you try it without your own file. Ham radio operators (who call Morse ‘CW’) can use it on receiver audio, and puzzle fans can crack audio clues. In class it turns an abstract code into something students can see as well as hear.
How to use it
- Open the tool and choose Upload audio or Listen (microphone).
- Pick an Alphabet if the message is not in International Morse.
- To decode a file, choose it or drag it onto the box. Formats such as MP3, WAV, OGG, M4A and WebM usually work, up to about 30 minutes or 100 MB. Press Try a sample if you just want to explore.
- Read the text and the dots and dashes. Leave ‘Find the tone for me’ checked, or uncheck it and set the tone slider by hand. Adjust Sensitivity and Speed if letters look wrong.
- To listen live, press Start listening, give microphone permission, then play your Morse close by. ‘Lock on this tone’ helps if it keeps losing the pitch.
- Copy the text or download it as a .txt file.
More tips
- Phone voice-recorder apps often have noise reduction or voice enhancement – turn it off, because it can erase the gaps.
- A # in the text means a pattern didn’t match the chosen alphabet. Check those codes by hand on the alphabet chart – a good extension activity on its own.
Ideas for the classroom and homeschool
- Grades 3–5Mystery message: make a WAV file of a clue with the translator, play it to the class, let students try to decode it by ear, then reveal the answer with the decoder.
- Grades 6–8Sound and waves: use the spectrogram and waveform to show that each beep is a steady frequency turned on and off. Compare a high tone and a low tone.
- Grades 9–12Physics or computer science: add noise to the sample and test how the decoder copes. Discuss signal-to-noise ratio and why narrow filters help isolate one tone.
- Grades 9–12Evaluating technology: read the tool’s stated limits (speech, music and very weak signals can cause errors) and debate when automated decoding can and can’t be trusted.
Questions
Is my recording sent anywhere?
No, according to the tool. Files are opened and analyzed by your own browser on your device, and microphone sound is processed as it arrives without being stored or uploaded.
Why are some letters wrong?
Background noise, other tones, uneven hand sending or very faint beeps can all confuse it, just as they would a human listener. Try changing the sensitivity or setting the tone manually.
Can it decode Morse from a radio?
Yes. Either hold the radio’s speaker near the microphone or save its audio as a file. It handles tones between 300 and 1,500 Hz, with speeds from around 5 wpm up to about 40 wpm.
How is this different from the translator?
The translator works with typed text and typed dots and dashes. This tool works with sound.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.
Microphone access requires browser permission, so follow your district’s device policy. Only decode recordings you have the right to use.