AI Sound Extender

This tool stretches a sound to a longer target length while keeping it continuous. It reads the clip's beats and section boundaries, then repeats and rejoins the right parts so the longer version doesn't snap back to an obvious loop or land on a hard splice. It runs in your browser, it's free, and there's no signup or install.

Upload an MP3 or WAV, set the new length you want, and the tool finds natural points to extend from. Preview the result, drag the cut points if you'd rather join somewhere else, then export the longer file.

It's built for sound that has to cover a fixed runtime. A 20-second background bed that needs to run under a two-minute video, an ambient loop that has to fill a slideshow as it grows, or a short clip you want padded out to a round 60 seconds for a timed segment.

Extending works best when the audio has a steady beat or a repeating texture, since that gives the tool clear places to add length. A clip made of one-off, non-repeating moments has fewer clean seams to work with.

Does it actually sound continuous? Because the join lands on detected beats and section edges instead of a fixed timestamp, the extra length usually blends in, and you can nudge the points yourself if one spot isn't clean.