CalConverters

Audio Speed Changer

Drop an audio file below, set the speed from 0.25x to 4x with the pitch preserved, preview live, then save as MP3 or WAV.

Files never leave your device

Drop an audio file here, click to browse, or paste

MP3WAVM4AAACOGGFLACWEBA

What This Tool Does

This speed changer makes audio faster or slower without changing its pitch — slow a guitar solo to 75% to learn it, speed a lecture to 1.5x, or stretch a clip to fit a video. Drop a file, set the speed, listen live, and save as MP3 or WAV.

Everything runs on your device through a time-stretching engine (SoundTouch, the same algorithm family used by professional players): no upload, no queue, no account.

Practice, Podcasts, and Precision

Use caseTypical speed
Learning an instrument part0.5x–0.75x
Language practice0.75x–0.9x
Podcasts and lectures1.25x–2x
Transcription0.5x–0.75x
Tip: Speeds between 0.5x and 2x sound the most natural. Extreme values (0.25x, 4x) still work, but time-stretching artifacts become audible — fine for analysis, less so for listening.

Live Preview, Exact Export

Press Play and drag the slider — the tempo changes instantly, mid-playback, with the pitch pinned in place. The export renders through the identical engine with the same setting, so the saved file matches what you tuned by ear. The editor shows the output length next to the speed, so you always know how long the result will be.

Your Audio Never Leaves Your Device

The decoder is the browser's own; the time-stretch engine and the MP3 encoder are small WebAssembly/worklet builds that run locally. Close the tab and nothing remains.

Frequently asked questions

Is this speed changer free?
Yes. No sign-up, no watermark, no limits. Everything runs inside your browser, so there is nothing to pay for.
Does my audio get uploaded?
No. Decoding, the live preview, and the final render all happen locally in your browser. Your file never leaves your device.
Does changing the speed change the pitch?
No — that's the point of this tool. A time-stretching engine keeps the pitch exactly where it was, so voices don't turn into chipmunks when you speed up or slow down.
What speed range is supported?
From 0.25x (four times slower) to 4x (four times faster), in steps of 0.05. Quick preset buttons cover the common values like 0.75x, 1.25x, 1.5x, and 2x.
How does speed affect the file's length?
Length scales inversely: at 2x a one-minute clip becomes 30 seconds; at 0.5x it becomes two minutes. The editor shows the resulting length before you save.
Can I hear the new speed before saving?
Yes — press Play and drag the slider while listening; the speed changes instantly without stopping playback, and the export uses the same engine you just heard.
Can I combine speed with other edits?
Yes. The same editor has Trim, Volume, Equalizer, and Pitch tabs — every active effect is applied together in a single export.
Which formats can I load and save?
Load MP3, WAV, M4A/AAC, OGG, or FLAC. Save as MP3 (high-quality VBR) or uncompressed WAV.