Audio Speed Changer

Speed audio up to 4× or slow down to 0.25×, useful for podcasts and language practice.

Your audio stays on your device. Processing happens locally in your browser.

Drag & drop an audio file

or click to browse — MP3, WAV, M4A, AAC, OGG, FLAC

What is this tool? Audio Speed Changer?

Speeding up podcasts to fit them in a commute, slowing down a song to learn a riff on guitar, or making a lecture digestible, speed changing is one of the most useful audio tools for everyday use. This tool uses linear interpolation to resample your audio. As is standard for "speed change without preserving pitch", faster playback raises the pitch and slower playback lowers it, which is what most users actually want.

How do you use this tool? Audio Speed Changer

  1. Upload audio, Drop any browser-supported audio file.
  2. Pick a speed, Use the slider or one of the presets. 1.5× and 2× are great for podcasts; 0.5× for music transcription.
  3. Apply and preview, Hear the result before saving.
  4. Download, Save the time-stretched WAV file.

Common Use Cases

Review podcasts and lectures faster

Increase playback speed to move through spoken content more efficiently.

Practise language listening

Slow speech to hear pronunciation, word boundaries, and difficult phrases more clearly.

Create timing variations

Adjust music, narration, or effects to fit a target duration during rough editing.

Transcribe difficult recordings

Reduce speed while replaying dense or unclear passages.

Why is this tool useful?

Wide speed range

Explore subtle adjustments or substantial slowdowns without a full digital audio workstation.

Immediate preview

Listen before export and choose the fastest or slowest setting that remains understandable.

Useful learning control

Repeat difficult sections at a manageable pace for transcription, pronunciation, or instrument practice.

Best Practices

  • ✓ Make small changes first, such as 0.8× or 1.25×, because extreme settings reduce intelligibility and may introduce artefacts.
  • ✓ Check whether the implementation preserves pitch. A basic resample changes pitch and speed together, while time stretching can keep pitch closer to the original.
  • ✓ Use headphones when evaluating speech clarity and musical artefacts.
  • ✓ For transcription, slow only the difficult section rather than exporting an entire long recording at an extreme rate.
  • ✓ Keep the original file and document the chosen speed when timing must be reproducible.

Practical examples

Speed up a lecture
Input
10-minute recording, speed: 1.5×.
Output
A file lasting about 6 minutes 40 seconds. Speech becomes faster, and the result should be previewed for intelligibility.
Slow down language practice audio
Input
2-minute clip, speed: 0.75×.
Output
A file lasting about 2 minutes 40 seconds, making individual words easier to follow.

Frequently Asked Questions

Resampling without time-stretching changes pitch with speed. Pitch-preserving time-stretch (PSOLA, phase vocoder) needs a much heavier algorithm and is on our roadmap.

Linear interpolation introduces a tiny amount of high-frequency softening. For voice content it's inaudible; for high-quality music, use a DAW.

No. The tool creates a new result in the browser. Your original remains unchanged unless you overwrite it after downloading.

The tool does not add ownership restrictions to your output. You remain responsible for rights to the source material and for complying with third party licenses.

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