Decode Morse code from audio
Choose an audio file or drop it on the box, and the Morse code reader does the rest. It looks for the strongest tone that switches on and off, measures every beep and gap, and turns them into letters. You see the dots and dashes, the decoded text with times, the speed in words per minute and the pitch of the tone.
Click any word in the text to hear that part of the recording again, or click the waveform. If the result looks wrong, move the sensitivity slider or set the tone yourself and the file is decoded again straight away.
Listen mode works the same way in real time. Press Start, allow the microphone, and play the Morse code near it. A scrolling picture shows the beeps and the threshold line, and a small spectrum shows the tone the decoder has locked on to.
A Morse code audio translator that stays on your device
Your recording is opened by your own browser and analysed on your device. It is never uploaded, stored or sent to us, so you can decode private messages, radio recordings and puzzle sound files safely. Files can be up to about 30 minutes long and 100 MB.
Most browsers can read WAV, MP3, M4A (AAC), OGG (Vorbis or Opus) and WebM audio. If a file will not open, save it again as WAV or MP3 and try once more. Video files often work too, as long as your browser can read their sound.
CW decoder for radio amateurs
Radio amateurs call Morse code CW. On a receiver it usually sounds as a tone between about 500 and 800 Hz, set by your beat frequency oscillator or CW pitch control. The decoder searches from 300 to 1,500 Hz, so any normal CW pitch is found automatically. Use Tone to type the pitch yourself if two signals are close together.
For the best results, use a narrow CW filter (250 to 500 Hz), turn off AGC or set it to slow, and keep the audio level comfortable rather than loud. From an SDR, record the demodulated audio in CW or USB mode, or play it into the microphone. The decoder follows slow drift and changes of speed from about 5 to 40 words per minute, and copes with Farnsworth spacing.
Machine-sent CW decodes very well. Hand-sent CW with a straight key or a bug decodes well when the sender keeps an even rhythm. Very weak signals, fast fading, static crashes and several stations on the same pitch will cause mistakes, as they would for a person copying by ear.
Tips for a clean recording
Record close to the sound, in a quiet room, without music or talking over the Morse. One clear tone works far better than several. Avoid speaker phones and video calls, which may cut out the gaps between beeps.
If you record on a phone, turn off any noise reduction or voice enhancement in the recorder app. A small amount of background hiss is fine: the decoder uses a narrow filter around the tone and adjusts its threshold to the noise.
Honest limits
No Morse code decoder is perfect. Speech, music, wind and other tones can be mistaken for Morse, very uneven keying can be read as the wrong letters, and very short or very weak beeps may be missed. Codes that are not in the chosen alphabet are shown as # with their dots and dashes listed, so you can check them by hand on the Morse code alphabet chart.
Questions and answers
How do I decode Morse code from an audio file?
Open the Upload audio tab, choose the file or drop it on the box, and wait a moment. The decoded text appears with times. You can adjust the sensitivity or the tone and it decodes again instantly.
Which audio formats can it read?
Whatever your browser can play: usually WAV, MP3, M4A (AAC), OGG and WebM. Files up to about 30 minutes and 100 MB are accepted.
Is my recording uploaded?
No. The file is read and decoded in your browser on your own device. Nothing is sent to us or stored.
Can it decode CW from my radio?
Yes. Play the receiver audio near your microphone or record it to a file. Tones from 300 to 1,500 Hz and speeds from about 5 to 40 words per minute are handled, and a narrow filter on the radio helps.
Why are some letters shown as #?
A # means the dots and dashes did not match any letter in the chosen alphabet. Their codes are listed under the text so you can check them.
What is the difference between this and the Morse code translator?
The translator turns typed text into Morse code and typed dots and dashes back into text. This page listens to Morse code sound and turns it into text.