Morse Code TranslatorHow to decode Morse code from sound
- Live: press Start listening, allow the microphone, and play the sound near your device. Letters appear as they come in. Press Stop when you are done.
- From a file: press Open audio file and pick a recording. The whole file is read at once, which is often more accurate than live listening.
- Check it: press Open in translator to play the result back, slow it down, or fix a letter.
Think of it as a Morse code audio translator: sound goes in, English text comes out. Not sure it works? Press Try a sample. It makes a short message in your browser and decodes it.
How the decoder works
The decoder looks for the loudest steady tone between 300 and 1500 Hz. Most Morse code is sent in that range. It then checks the power of that tone every few milliseconds to see when the tone is on and when it is off.
Next it sorts the beeps into short and long ones. The short ones are dots and tell it the speed. A long beep is a dash. Then it looks at the gaps. The ITU rules say a gap inside a letter is one dot, between letters three dots, and between words seven dots. The decoder uses that to split the letters and words.
Because it learns the speed from the signal, you do not need to set it. It also handles Farnsworth spacing, where letters are fast and the gaps are long. In our tests we decode messages from 12 to 25 WPM at different tones with added noise.
Tips for better results
- Use a file when you can. A clean recording gives the best text.
- Turn off music, fans and TV. Background noise can sound like a dash.
- Hold the phone close to the speaker, but not so loud that the sound breaks up.
- Hand sent code with uneven gaps may come out with letters run together. Look for words in the Morse box and add spaces by hand in the translator.
- Radio signals that fade in and out may drop dots. Listen to a stronger signal if you can.
Where to find Morse code to decode
The ARRL station W1AW sends code practice on the air at speeds from 5 to 40 WPM. Airplane navigation beacons also send their names in Morse code. The FAA says pilots use that Morse ID to check they are tuned to the right station. You can also make your own practice files with our Morse code generator.
To learn to decode by ear, see how to learn Morse code.
Frequently asked questions
How do I decode Morse code from audio?
Press Start listening and hold your phone or computer near the sound. Or press Open audio file and pick a recording. The decoder finds the tone and speed on its own and writes out the letters.
Which audio files work?
Any file your browser can play, such as WAV, MP3, M4A, OGG or the sound track of many MP4 videos. Clean recordings of one steady tone work best.
Why does the decoder make mistakes?
Noise, echo, fading radio signals and other sounds can hide the beeps. Uneven hand sent code is also hard, because the gaps change. Try a quieter room, move closer, or use a file. Very fast code above about 40 WPM is harder to read from a microphone.
Is my audio uploaded?
No. All decoding happens in your browser with the Web Audio API. Nothing you play or record leaves your device.
Can it decode flashing light or a video of blinking?
Not yet. It reads sound only. For light, write down short and long flashes and type them into the translator.