Audio looper

Loop audio in three steps

1. Choose an audio file or a video, or try the included beat. The whole file is selected to start with.
2. Drag across the waveform over the part to repeat, or type its start and end. Press Preview loop to hear it wrap around, and adjust the ends or the crossfade until the seam disappears.
3. Choose how many times to repeat it, or a total length such as 10:00, then press Make loop, listen, and download the MP3 or WAV.

Looping versus trimming

The audio trimmer keeps one copy of a section and throws the rest away. The looper starts the same way, with a section of the file, but then repeats it back to back to make something longer: a four-bar drum groove that runs for three minutes of practice, a ten-second rain recording stretched to an hour-long sleep track, a short jingle that has to fill a 30-second ad slot, or one tricky guitar phrase repeated twenty times so you can learn it. Trim when you need less of a recording; loop when you need more of one part of it.

How the seamless crossfade works

Each copy starts slightly before the previous one ends, and the two overlap for the crossfade time you choose, 10 ms to 1 second. The fade is not a fixed curve. The looper measures how alike the end and the start of your section are over that overlap. Unrelated sound, such as a cymbal decaying into the next downbeat, gets an equal-power fade, which keeps the level steady when two different sounds mix. Sound that matches itself, such as a held synth pad or a drone cut on a whole cycle, gets gains that add up to one, because an equal-power fade there would swell by up to 3 dB at every loop point. Between the two, the gains are solved so the combined level stays constant. With the crossfade set to none you get hard cuts, which are right for a sample cut exactly on the beat, and click when they are not.

What the preview plays

Preview loop plays one period of the finished loop on repeat: the section with the crossfade already baked into its start, played by the browser’s own sample-accurate loop. That is exactly what the middle of your download sounds like, so if the seam is clean in the preview, it is clean in the file. Move the loop points or change the crossfade while it plays and the preview follows. Repeat-to-length mode cuts the last copy wherever the length ends; add a fade out of one or three seconds so it does not stop mid-note.

Limits and privacy

A loop can be repeated up to 100 times and can be up to 20 minutes long. The whole result is built in memory before it is encoded, so a phone may struggle near the top of that range, and a long WAV is large (about 10 MB per minute in stereo). For longer sleep or ambience tracks, make a 20-minute loop and repeat the file in your player. The file is decoded and looped in your browser tab; nothing is uploaded, there is no signup and no watermark. The looper repeats audio only; a video’s soundtrack can be looped, but the picture is not kept.