Morse Code Decoder
Decode Morse code from sound. Play Morse code to your microphone or upload an audio file, and the letters appear as the beeps are heard. It finds the tone and the speed by itself, and the audio never leaves your device.
Press Listen and play Morse code near your phone or computer.
Reads about 5 to 40 words per minute and tones from 250 to 2000 Hz. Upload WAV, MP3, M4A, OGG or any audio your browser can play.
How to decode Morse code from audio
- Press Listen and allow the microphone when your browser asks.
- Play the Morse code close to the microphone: a video, a voice message, a radio, a buzzer or someone sending with a key.
- Watch it decode. The lamp lights with every beep and the letters appear as they finish. The decoder works out the tone and the speed from the first few letters, so there is nothing to set.
- Copy the text, or open it in the Morse code translator to see the code and play it back.
Have a recording? Press Audio file and choose it. A whole file is decoded in a moment, without playing it.
Tips for a clean decode
- Use a quiet room and turn the sound up, but not so loud that the speaker rattles.
- Hold the phone a hand's width from the speaker. One Morse signal at a time works best.
- Machine-sent Morse decodes almost perfectly. Hand-sent Morse works too, as long as dashes are clearly longer than dots.
- If the letters come out wrong, press Clear: the decoder forgets the old tone and speed and learns them again.
What this Morse code reader can and can't do
It reads steady beeps: radio CW, Morse in videos and games, apps, buzzers, and files from the Morse code generator. It copes with background noise, slow fading on radio signals, Farnsworth spacing and uneven hand-sent timing.
It can't read flashing light, knocking or tapping sounds (they have no steady tone), two signals at once, or a signal buried under loud music or voices. For Morse written as dots and dashes, use the translator.
How the decoder works
First it looks for the tone: a short frequency analysis (FFT) finds the pitch that stands clearly above the background. Then a narrow filter tuned to that pitch measures its level every 5 milliseconds, and an adaptive threshold between the noise and the tone decides when the beep is on. Finally the decoder measures how long a dot lasts in this signal, which tells dots from dashes and the short gaps inside a letter from the longer gaps between letters and words. The timing rules it relies on are explained in how Morse code works.
It is tested on generated Morse from 5 to 40 WPM with heavy background noise, radio-style fading and hand-sent timing that wobbles by up to 20%.
Frequently asked questions
How do I decipher Morse code from a video?
Play the video on one device and press Listen on MorseBeep on another, holding the microphone close to the speaker. You can also play the video on the same computer: most browsers let the microphone hear the speakers. If you can download the audio, upload the file instead for the cleanest result.
Is the microphone recorded or uploaded?
No. The sound is analysed in your browser as it arrives and then thrown away. Nothing from the microphone or from an uploaded file is saved or sent to a server.
Why are some letters wrong or shown as #?
A # is a group of dots and dashes that is not a Morse character, usually because two letters ran together or a beep was missed. Background noise, a second sound at the same time, or very uneven hand-sent timing can cause it. Move the microphone closer, turn the volume up, and press Clear so the decoder learns the tone and speed again.
What speeds can the Morse code decoder read?
From about 5 to 40 words per minute, including Farnsworth spacing. You never set the speed: the decoder measures the length of a dot from the first few letters and keeps adjusting as it hears more.
Can it decode Morse code from flashing light or a picture?
Not yet; this decoder reads sound. If you have Morse code written as dots and dashes, paste it into the Morse code translator, which turns it into English straight away.
Does it work on iPhone and Android?
Yes, in Safari, Chrome and other modern browsers. Allow the microphone when your browser asks, and keep the page open and the screen on while it listens.