Reverse Audio

Play a song, a voice message or a sound effect backwards. Reverse the whole file, or only a part of it, for example one word or a cymbal hit for a classic reverse-swell effect. Listen for "hidden messages", make sound effects or check how a phrase sounds reversed. Everything happens in your browser; the file is never uploaded.

How to use this tool

1. Choose one or more audio files.
2. Leave the times empty to reverse everything, or enter the part to reverse (from and to).
3. Pick MP3, WAV or the same format as the original.
4. Press Calculate, play the result and download it.

Formula

reversed[i] = original[N − 1 − i] for every sample i of the chosen part (N samples)

Each channel is decoded and its samples are put in the opposite order, so the length and the sound's spectrum stay the same while everything in time runs backwards: echoes swell before the sound, and piano notes fade in instead of out. When only a part is reversed, 5 ms fades on both sides of each join stop the cut from clicking. WAV output is exact; MP3 and other lossy formats are encoded again.

Example

A 12.4-second voice message reversed stays 12.4 s long: the last word is heard first, backwards. Reversing only 0:03 – 0:04.2 turns just that 1.2-second part around and leaves the rest playing forwards.