Morse Code Audio Decoder

Decode Morse Code from an Audio File

This tool reads Morse timing from an MP3, WAV, OGG, M4A or other audio format supported by your browser. It turns detected tones into dots and dashes, then converts those groups into readable text.

The audio is decoded and analysed locally. The file is not uploaded to ToolMi or stored on a server.

How to use the Morse audio decoder

1. Drop an audio file into the upload area or select one from your device.
2. Listen to the preview to confirm that it contains a clear Morse tone.
3. Choose the international Latin or Russian Cyrillic alphabet.
4. Let the tool detect the dot duration automatically, or enter it in milliseconds.
5. Copy the detected Morse sequence and decoded text, or download both as a text file.

What the automatic analysis measures

• The local noise floor and signal level.
• Tone and silence runs in short time windows.
• Short tones as dots and longer tones as dashes.
• Intra-character, character and word spacing.
• A likely dot duration and timing confidence score.

The confidence value describes how closely the timing matches the standard 1:3:7 Morse rhythm. It does not guarantee that every decoded character is correct.

Best audio for accurate decoding

• Use a single, steady tone with little background noise.
• Trim long introductions, speech or music where possible.
• Avoid recordings with several Morse stations playing at once.
• Keep the playback speed constant throughout the recording.
• If automatic spacing is wrong, enter the duration of one dot manually.

Dot duration and Morse speed

Standard Morse timing uses one unit for a dot, three units for a dash, one unit between symbols, three units between letters and seven units between words. The decoder estimates the shortest recurring tone as the dot unit.

A manual value is useful for noisy recordings or messages containing mostly dashes. For example, if a dot lasts about 100 ms, enter 100 and decode again.

International and Russian alphabets

The same dot-and-dash pattern can represent different letters in different Morse alphabets. Choose International for Latin A–Z and Russian for Cyrillic output. Numbers and common punctuation are supported in both modes.

Privacy and browser support

Processing takes place through the browser Web Audio API. Format support can vary by browser and operating system. WAV and MP3 are generally the most portable choices.

Frequently asked questions

Can it decode Morse from speech or music?

Not reliably. This decoder is designed for clear electronic or radio-style Morse tones.

Why are some letters shown as �?

The detected dot-and-dash group does not exist in the selected alphabet. Check the recording, alphabet or dot duration.

Does the tool change my audio?

No. It only reads the file and creates a separate text result.