Mp3toMidi is an online tool that converts MP3 audio files into MIDI files, enabling users to extract musical note data such as pitch, timing, and velocity from recordings. The service is designed to work best with clear, focused audio sources such as a single melody, piano phrase, vocal line, or guitar riff. It supports MP3, WAV, and M4A file formats, subject to upload limits based on the user’s account tier: Free accounts allow files up to 10 MB and 10 minutes in length, while Basic and Standard tiers increase these limits to 25 MB and 15 minutes, and 50 MB and 20 minutes, respectively. For AAC or FLAC files, the site directs users to a separate dedicated converter. The conversion process is done entirely in the browser, requiring no desktop software or plugin installation. Users upload an audio file, and the service validates the audio, creates a conversion job, and analyzes the audio to identify note events. A preview of the resulting MIDI is available before downloading, allowing users to check the transcription quality. The final output is a standard .mid file that can be imported into digital audio workstations (DAWs) such as Ableton Live, Logic Pro, and FL Studio, as well as notation software or samplers. Free and guest users can evaluate the first 30 seconds of conversion before committing to a longer paid conversion. Typical use cases include creating an editable starting point for arrangement, practice, transcription, or triggering virtual instruments. The tool is intended as a practical first step rather than a final arrangement, leaving room for users to correct or develop the result within their own workflow. Technical requirements are minimal: a modern web browser and an internet connection. The service also offers a dedicated workflow for high-quality WAV recordings, and for users who prefer an alternative file format, a separate audio-to-MIDI converter is provided.