Audio tools
23 tools
Tools for working with audio files: recording, conversion, editing, transcription, and more.
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BPM auto-detect — estimate the tempo of an audio file
Drop an audio file (MP3 / WAV / M4A / FLAC / OGG) and we estimate the BPM in-browser using a low-pass filter + peak picker + histogram. Great for finding the tempo of a DJ partner track, checking sample packs, matching dance / running cadence, or grabbing a source BPM before running bpm-time-stretch. Half-tempo and double-tempo candidates are also shown so you can override 4-on-the-floor misreads (60 vs. 120). Everything stays in your browser.
audiotempo
Audio channel merge — two mono files into a stereo L + R
Combine two mono audio files (MP3 / WAV / M4A / FLAC / OGG) into one stereo file. The first file becomes the left channel, the second becomes the right; we interleave them and output one stereo WAV / MP3. Useful for putting two-mic interview takes into a single L/R file, faking stereo from a mono source, or reversing audio-channel-split. When lengths differ, truncate to the shorter file or pad the shorter one with silence — your choice. Everything stays in your browser.
audiomerge
Audio channel split — stereo to two mono files
Split a stereo audio file (MP3 / WAV / M4A / FLAC / OGG) into separate left and right mono WAV / MP3 files. Useful for interview / dictation / Zoom recordings captured with one speaker per channel, isolating noise on one side, or pulling a single channel into your DAW. Mono input passes through as a single file. Everything stays in your browser.
audio
Audio format convert — MP3 / WAV / M4A / OGG / FLAC
Convert audio files to mp3 / wav / m4a / ogg / flac. ffmpeg.wasm picks an encoder based on the chosen extension and re-encodes the file entirely in your browser. Supports batch processing and a single ZIP download.
audioconversion
Audio cut — trim a range with no re-encoding
Trim an audio file to a chosen range with ffmpeg.wasm stream copy — no re-encoding, original codec and extension preserved. Cut points snap to the nearest keyframe. Supports batch processing and a single ZIP download.
audiosplit
Audio fade — apply fade-in / fade-out in seconds
Add fade-in at the start and fade-out at the end of audio files. ffmpeg.wasm's afade filter handles MP3 / WAV / M4A / OGG / FLAC. Supports batch processing and a single ZIP download. Audio files never leave your device.
audio
Audio merge — concat multiple files into one
Concatenate multiple audio files via the ffmpeg.wasm concat demuxer. Reorder by drag. Stream copy keeps codec untouched, but all inputs must share the same codec and sample rate.
audiomerge
Audio metadata strip — ID3 / Vorbis / iTunes tags
Drop ID3, Vorbis comment, iTunes and other tags from audio files using ffmpeg.wasm — entirely in your browser. Uses stream copy so the codec, quality and file extension are preserved. Supports batch processing and a single ZIP download.
audioEXIF
Noise Generator (White / Pink / Brown)
Synthesise white, pink and brown (red) noise in your browser with live playback and WAV download. **White** has flat energy across frequency (sounds bright). **Pink** has flat energy per octave (1/f spectrum, close to many natural sounds). **Brown** falls off at -6 dB/octave for a deep, ocean-like sound. Useful as a focus-aid masking track, infant sleep aid, tinnitus relief, or as a test signal for audio equipment. Download any duration from 0.5 s to 60 s as 44.1 kHz / 16-bit / mono WAV. Runs entirely in your browser — nothing is uploaded.
generate
Audio pitch shift — change key in semitones while keeping tempo
Pitch-shift audio files (MP3 / WAV / M4A / AAC / FLAC / OGG / Opus) by semitones (±12 = one octave) without changing playback speed. Powered by soundtouchjs (SoundTouch library) running on Web Audio API samples. Great for karaoke key changes, matching keys across language-learning clips, tweaking narration tone for videos, or stylized voice effects. Export to WAV or MP3 with batch support. Your audio stays inside your browser — nothing is uploaded.
audio
Noise reduction — RNNoise (ML) suppresses hiss / fan / keyboard noise
Upload an audio file and the tool uses RNNoise (Xiph.org, BSD-3-Clause) — a small neural network trained on noisy speech — to suppress fan noise, keyboard clatter, white noise, and breath sounds, returning a denoised WAV. Audio is resampled to 48 kHz mono with the Web Audio API and fed through the WebAssembly RNNoise model in 10 ms / 480-sample frames, alongside a voice activity (VAD) estimate. The model preserves speech while cleaning up the background, making it ideal for post-production of Zoom recordings, podcast raws, livestream clips, and meeting captures. Audio never leaves the browser.
audio
Audio reverse — flip audio backwards to WAV / MP3
Reverse audio files (MP3 / WAV / M4A / AAC / FLAC / OGG / Opus) entirely in the browser and export to WAV or MP3. Great for ASMR, music production, social media, or sound design. Web Audio API decodes the file, samples are flipped per channel (stereo handled correctly), then re-encoded. Batch multiple files and grab them as a ZIP. Your audio never leaves your device.
audioreverse
Audio tempo shift — change speed while keeping pitch
Stretch or compress audio files (MP3 / WAV / M4A / AAC / FLAC / OGG / Opus) by tempo (playback speed) without affecting pitch. Powered by soundtouchjs (SoundTouch library time-stretching) running on Web Audio API samples, from 0.5x (half speed) to 2.0x (double). Great for slowing down language-learning clips, transcribing tricky musical phrases, refining narration timing, or producing a 2x podcast cut. Export to WAV or MP3 with batch support. Your audio stays inside your browser — nothing is uploaded.
audio
Audio file transcription — Whisper, multilingual
Upload an MP3 / WAV / M4A file and transcribe it with Whisper running inside your browser. Long files are chunked automatically. No audio or model data leaves your device. Performance and supported model size depend on your hardware (CPU / GPU / RAM).
audiotranscriptionAIextract
Trim silence from audio — auto-cut leading and trailing silence (ffmpeg.wasm)
Automatically trim the leading and trailing silence from MP3 / WAV / M4A / AAC / OGG / OPUS / FLAC files using ffmpeg.wasm's silenceremove filter. Great for removing dead air at the start of recordings, the awkward pause before a talk, or an unnecessarily long fade-out at the end of a podcast. Tweak the threshold (dB) and minimum silence length (seconds) and choose which side(s) to trim. Batch process and grab a single ZIP. Files never leave your device — every step runs in the browser.
audioextract
Audio volume — adjust by dB or linear multiplier
Adjust the loudness of audio files in bulk via ffmpeg.wasm's volume filter. Use the dB slider (-30 to +30 dB) or the linear multiplier (×0.03 to ×31.6). +6 dB ≈ 2x, -6 dB ≈ half. To avoid clipping, try negative values first and compare. Supports batch processing and a single ZIP download. Runs entirely in your browser — audio never leaves your device.
audio
BPM tap — measure tempo by tapping along
Tap a button (or press space) along with a song and the tool computes BPM from the recent inter-tap intervals using the median. Outlier-resistant median + IQR-based stability, up to 16 recent taps, with reset / history clear. Optional Web Audio metronome plays in sync with the detected BPM. All processing runs in your browser.
audiotempo
BPM time-stretch — match a target BPM from your source
Enter the source BPM and target BPM, and soundtouchjs (SoundTouch) re-times the audio by `tempo = target / current`. Pitch is preserved, so it's perfect for DJ-style beat matching, music practice at a specific tempo, podcast pacing alignment, or dance rehearsals. Batch multiple files toward a single target. Output to WAV / MP3 — your audio never leaves the browser.
audiotempo
Metronome — BPM, time signature, and click sound
Web Audio API metronome with BPM (30–300), time signature (1–12 beats), and click sound (click / woodblock / cowbell). First beat is accented with a higher pitch, and the current beat is highlighted live. Look-ahead scheduling keeps timing accurate to under 1 ms drift, with volume / mute control. Pair with bpm-tap to play back a tapped tempo. Everything is synthesized in your browser — nothing uploaded.
audiotempo
MIDI File Info Viewer
Drop a MIDI file (.mid / .midi) to inspect tempo, time signature, key signature, PPQ, track count, per-track instrument (GM family), note count, duration, channel, and copyright / text events. Read-only, runs entirely in your browser via @tonejs/midi (MIT).
audioextract
About this category
Convert, edit, and analyze audio files entirely inside your browser. Built around ffmpeg.wasm, these tools handle the major audio formats — MP3, WAV, M4A, AAC, OGG, Opus, FLAC, and more.
Useful when you need to edit a voice memo right after recording it, clean up a confidential interview without uploading it anywhere, trim silence out of a long meeting recording, transcribe audio locally with Whisper, or strip metadata before sharing a file.
What you can do
- Record a voice memo and edit / export to MP3 in place
- Convert between MP3 / WAV / M4A / FLAC and other formats
- Cut a clip from an audio file, or merge several files into one
- Adjust volume and add fade-in / fade-out
- Auto-trim silence from meeting recordings or voiceovers
- Local, in-browser transcription powered by Whisper
- Strip metadata (title, artist, etc.) from audio files
Category FAQ
- Are audio files really converted without uploading them?
- Yes. ffmpeg.wasm (the WebAssembly build of ffmpeg) runs inside your browser, so your audio file is never sent to a server. The first run downloads about 30 MB of ffmpeg.wasm — that's the tool's code, not your file.
- Which audio formats are supported?
- All major formats ffmpeg can handle (MP3, WAV, M4A, AAC, OGG, Opus, FLAC, WebM, and so on). MIDI parsing and audio recording have their own dedicated tools.
- Is transcription also done in the browser?
- Yes. voice-transcribe and audio-transcribe load a Whisper model into your browser and run inference locally. Neither the audio nor the transcribed text is sent out. Only the first download of the model needs a connection.
- Is there a limit on audio length?
- There is no server-side limit, but long audio uses a lot of memory. About one hour is a comfortable target; for anything longer, split it first with audio-cut.