Free tools

Audio tools.

Trim, join, convert, compress, transcribe, record — plus the odd jobs that come with recording on a phone. All free, all running entirely in your browser: no account, no uploads, no size limits.

Recorder

Free Online Voice Recorder

A free online voice recorder that needs no download and no account, and uploads nothing. Live waveform, pause and resume, crash recovery, non-destructive trim and WAV export, all on your device. Works with the network off.

Any device · instantOpen tool →

Transcription

Free Audio to Text Online

Free audio to text online — unlimited, no sign-up, and nothing uploaded. Whisper runs on your own device in the browser, with clickable timestamps, 99 languages, inline editing and TXT, SRT, VTT, Markdown or JSON export. Works offline after the first load.

Any device · minutesOpen tool →

Converter

Free Online Audio Converter

Convert audio and video to MP3, WAV, M4A, Ogg, Opus or FLAC entirely on your device — nothing uploaded, no file size limit, no sign-up. Batch queue with ZIP download, trim before converting, metadata stripped by default, and even AMR or WMA handled by an on-device ffmpeg engine.

Any device · secondsOpen tool →

Compressor

Free Audio Compressor

Reduce audio file size on your own device: pick a quality preset, a target size in MB or a percentage, and the bitrate is solved for you. A/B the original against the compressed version at the same playhead before you keep it. Free, no upload, no sign-up.

Any device · secondsOpen tool →

Trimmer

Free Audio Trimmer

Cut audio online without uploading it. Drag handles across a waveform to keep the part you want — or cut a section out of the middle and close the gap. Type exact timecodes if you need to be precise, preview the cut before you commit, and download MP3 or WAV. Free, no sign-up, no size limit.

Any device · secondsOpen tool →

Joiner

Free Audio Joiner

Merge audio files into one track without uploading them. Add MP3, M4A, WAV or anything else, reorder them, then choose a silent gap or an equal-power crossfade between them. Files that disagree about sample rate or channels are matched automatically — the usual reason a merge comes back playing at the wrong speed.

Any device · secondsOpen tool →

Silence remover

Free Silence Remover

Cut dead air out of a recording without uploading it. The threshold is read from the recording's own noise floor rather than guessed, every pause is drawn on the waveform before anything is cut, and you can shorten pauses to a natural beat instead of deleting them. Shows exactly how much time you save.

Any device · secondsOpen tool →

Speed changer

Free Audio Speed Changer

Slow down or speed up audio and keep it as a file, not just a playback setting. Pitch is preserved by default — a slowed voice message still sounds like the person — using the same time-stretching approach ffmpeg uses, running in the tab. Or switch it off for the tape-speed effect on purpose.

Any device · secondsOpen tool →

Volume

Free Volume Booster & Normalizer

Make a quiet recording usable, or match a set of them to one loudness. Measures true perceived loudness in LUFS the way streaming platforms do, not just the loudest sample, then boosts to a target and limits the peaks so a boosted file gets louder rather than distorted. A/B the result against the original.

Any device · secondsOpen tool →

Inspector

Free Audio Metadata Viewer

Drop in an audio file and get a plain-English answer: what it actually is, when it says it was made, which software has written it, and whether it is carrying your location. Read entirely on your device — no upload, no sign-up. Honest about what metadata cannot tell you: it issues no authenticity verdict, because none is possible.

Any device · about a secondOpen tool →

Legal information

Recording Consent Checker

Can you record this conversation? Answer a few questions to see which recording-consent rules may apply where you and the other participants are, with the official statute behind every answer — and a clear way to ask permission.

Any device · about two minutesOpen tool →

Legal information

Audio Recording Evidence Checker

You already have a recording — what happens now? No tool can tell you whether it will be accepted, and this one refuses to pretend. Instead it ranks what will actually decide it for your situation, gives you a preservation checklist for tonight, and generates specific questions for a lawyer. HR and internal processes get their own answer, because they are not courts.

Any device · about three minutesOpen tool →

Diagnostic

Background Recording Troubleshooter

Recording stopped after a call, screen lock, battery saver or another app? Answer a few questions to get the likely cause, device-specific settings to check and a reliability test.

iPhone & Android · about one minuteOpen tool →

Compatibility

Will BlackBox Work on My Phone?

A realistic read on whether your iPhone or Android phone can record reliably in the background: a score out of 100 with every deduction explained, your storage and retention limits, the interruptions to expect, and a setup checklist for your device.

iPhone & Android · about one minuteOpen tool →

Calculator

Audio Storage Calculator

See how many MB or GB voice recordings use per hour, day and month at any quality — plus a cleanup schedule that stops your phone filling up.

Any device · instantOpen tool →

Record your whole day, privately.

BlackBox is a 24/7 background voice recorder with scheduling, on-device transcription and local storage. Free on iPhone and Android.

Download on theApp Store Get it onGoogle Play