No upload, 100% local, no account

Reverse audio

Reverse any audio file, the end becomes the start. Everything runs in your browser; your file never leaves your device.

How Reverse audio works

Audio reverse plays your audio file backwards: the final sample becomes the first, and everything in between is flipped. It is used in music production to create reverse-cymbal swells and reverse-reverb tails, in sound design to build tension, and by listeners curious about backmasking in old recordings. Drop a file and download the reversed version in seconds.

The reversal is done by ffmpeg compiled to WebAssembly, applying the areverse filter in a single pass on your own device; the file is never uploaded to a server. No account and no watermark. Supported formats include MP3, WAV, M4A, OGG, FLAC, and AAC.

Written by Bastien Sulyan

How to use Reverse audio, step by step

  1. Drop or select your audio file (MP3, WAV, M4A, OGG, FLAC, AAC).
  2. The tool processes it locally using the ffmpeg areverse filter.
  3. When the progress bar completes, a download button appears.
  4. Click Download to save the reversed file to your device.

Common use cases

  • Creating reverse-cymbal swells or riser effects for music production without cloud software.
  • Generating a reverse-reverb tail by reversing a dry track, adding reverb, then reversing again.
  • Checking a recording for suspected backmasking or hidden messages.
  • Sound design: reversing dialogue or ambient recordings to create uncanny textures.

Frequently asked questions

Does reversing audio upload my file to a server?

No. ffmpeg compiled to WebAssembly runs the areverse filter directly in your browser tab. Your file is read into in-browser memory, the sample order is reversed there, and the result is offered as a local download. Nothing is transmitted to Sunasty or any third party. Open your browser DevTools, go to the Network tab, and trigger the reversal: you will see no outbound request carrying your audio.

What exactly does the areverse filter do?

It reverses the order of every audio sample in the file. The first sample in the output is the last sample of the input, and so on down the line. The frequency content of each moment is preserved; only the sequence changes. No pitch shifting, no time stretching, no resampling: a pure time-reversal of the waveform.

Does the output keep my original format?

Yes. The reversed file uses the same container and codec as your input. An MP3 comes out as an MP3, a WAV as a WAV, and so on. There is no transcoding step, so audio quality is not degraded beyond a single ffmpeg pass.

Can I reverse only part of an audio file?

This tool reverses the entire file. To reverse a specific section, first trim the segment you want with the audio-cutter tool on this site, then reverse that clip, and optionally merge it back into the original.

What is backmasking, and can this tool detect it?

Backmasking is a recording technique where audio is reversed and embedded into a track. Listeners have long claimed to hear hidden messages when songs are played backwards. This tool just reverses audio; it does not interpret or analyze content. Whether you hear something meaningful in a reversed track is entirely your own perception.

Does audio reverse work offline?

Mostly. The areverse filter always runs on your device, your audio never leaves your machine. The one caveat is that the ffmpeg engine is a sizeable download fetched from this site the first time you run the tool; once that download and the page have both completed, you can disconnect from the internet before pressing the reverse button and the tool will work the same way.