Free Online DJ Tools
Change tempo, convert formats, adjust levels, transpose keys, and check audio quality.
Convert MP3, WAV, FLAC, OGG, and OPUS files directly in your browser.
Adjust one track at a time with automatic BPM detection, instant target-speed preview, and export.
Detect the BPM of multiple audio files directly in your browser.
Detect the musical key of multiple audio files directly in your browser.
Adjust one track at a time with original and adjusted waveforms, live sample-peak values, and sample-clipping-safe export.
View a full-track spectrogram, find the high-frequency cutoff, and compare it with the file’s declared quality.
Transpose songs by semitones without changing tempo, with Camelot guidance for the resulting key.
Choose the right tool for the job
SirenMix focuses on practical DJ prep: testing tempo changes, making compatible file copies, adjusting levels, transposing keys, and checking source quality before a set.
Use BPM Changer when you need to test tempo moves, preserve pitch, and export a new version before a set.
Use Audio Format Converter when a track needs a different format for playback hardware, storage, or sharing.
Read the linked guides when you need the theory behind the workflow, not just the output file.