ALL AUDIO TOOLS18
Reverse Audio
Reverse Audio Online — Free Backwards Audio Tool
Turn a clip back to front sample by sample, then export it as MP3, WAV or FLAC.
Nothing is enforced, but the file is decoded to 32-bit float in this tab — once for the waveform and once to reverse it, at roughly 20 MB per minute of 44.1 kHz stereo — with the reversed copy held beside the original.
About Reverse Audio
Reversing audio is the one effect that costs nothing at all in itself. The file is decoded to raw samples, each channel is walked from the last sample to the first into a new buffer of exactly the same shape, and that is the whole operation — no filter, no resampling, no interpolation, nothing that has to make a decision about the sound. Every sample that was in the file is still in the file, and the length comes out identical to what went in. The channel count and sample rate do too on the WAV and FLAC arms; MP3 is the exception, because it carries at most two channels and 48 kHz, so a surround or hi-res source is folded or resampled on the way out and the run says so. What it is used for is mostly play and mostly deliberate: reversed cymbals and risers, backwards-speech effects, the reversed-then-re-reversed reverb trick, checking whether a recording really does say the thing somebody claims it says. The cost, when there is one, lives entirely in the format you export to. WAV writes the reversed samples uncompressed at 16 bits, so nothing is thrown away, though a 24-bit source is still reduced to 16-bit on the way out. FLAC compresses them without discarding any, at roughly half the size of WAV, and is the export that costs nothing beyond the decode. MP3 is a fresh lossy encode: reversing a lossy source and exporting it as MP3 means the audio has been through two lossy encoders, which is worth knowing rather than worth avoiding at all costs. The reverse itself runs on the Web Audio API in this tab; a container your browser will not decode, and FLAC output, fall back to FFmpeg compiled to WebAssembly, which is downloaded only if one of those actually happens. Tags and cover art do not survive the decode.
Questions
Does reversing lose any quality?
The reverse itself loses nothing: each channel is walked from the last sample to the first into a new buffer of exactly the same shape, so every sample that was in the file is still in the file, and the length comes out identical. Any loss comes from the format you export to, not from the reversal — and that includes shape: WAV and FLAC keep the channel count and sample rate, while MP3 carries at most two channels and 48 kHz, so a surround or hi-res source is folded or resampled and the page says so.
Which output format should I pick?
FLAC if you want to keep everything — it compresses the reversed samples without discarding any, at roughly half the size of WAV. WAV is uncompressed but written at 16 bits, so a 24-bit source is reduced. MP3 is a fresh lossy encode, which means a lossy source reversed into MP3 has been through two lossy encoders.
Can I reverse just part of a file?
Not here — this reverses the whole file. Trim the section you want with the audio trimmer first, then reverse the result.
Is the video reversed too?
There is no video involved. This tool takes audio files and hands back audio files; if you drop a file with a video track it is the audio that is decoded, and nothing writes a picture back out.
Why does the waveform not look reversed?
Because it is the source's shape, drawn when the file lands. Painting the reversed bars would be a picture of a file that does not exist until the run finishes, and there is nothing to compare it against afterwards, so the canvas shows what you gave it.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and WebAssembly. Your files never leave your device — there is no server, no upload, no cloud processing.