AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I speed up or slow down audio while keeping the pitch natural?

Open AnyTool's Audio Speed Changer, drop in your file, and drag the speed slider to hear the change instantly with no encoding — pitch stays natural by default, or switch to a pitch-follows-speed mode for nightcore and slowed effects. Export keeps your chosen format with the tempo applied via ffmpeg. Everything runs in your browser — no upload, no watermark, no size cap, no CDN.

  • Instant zero-encode preview while you drag the speed slider
  • Pitch-preserved tempo, or pitch-follows-speed for nightcore/slowed
  • Independent semitone pitch shift and 1-tap presets
  • 100% in your browser — no upload, no watermark, no size cap

What is

Audio speed change

Changing audio speed alters playback tempo. With pitch preserved, the tempo changes but the voice or music keeps its natural pitch (ffmpeg atempo); with pitch following speed, both rise or fall together (resampling) for nightcore/vaporwave effects. A browser-based tool previews with HTMLMediaElement.playbackRate and encodes locally without uploading.

Audio Tools

Related terms

tempopitchatemponightcoreffmpeg

How to Change Audio Speed

Speed up or slow down audio in your browser.

15 secWeb browser
  1. 1

    Add audio

    Drop in any audio file — it stays on your device.

  2. 2

    Set the speed

    Drag the speed slider (pitch preserved or following) and listen instantly.

  3. 3

    Export

    Choose a format and download with the tempo applied — nothing is uploaded.

Result: A speed-adjusted audio file

Frequently Asked Questions

No — it runs entirely in your browser with a self-hosted engine.

The file never leaves your device and there is no size cap or watermark, unlike 123apps (server-side), Clideo/VEED (watermark) or AudioAlter (~50 MB cap).

Yes — pitch is preserved by default; you can also let it follow the speed.

A toggle switches between pitch-preserved tempo (for podcasts/practice) and pitch-follows-speed (for nightcore, slowed and vaporwave effects), and there is a separate semitone pitch slider.

Yes — dragging the slider changes playback instantly with no encoding.

Preview uses the media element's playback rate so you hear the new speed in real time; encoding to your chosen format only happens on download.

Detailed Explanation

Methodology

How the Audio Speed Changer Works

AnyTool changes audio speed entirely in the browser. Preview is instant and encode-free: a bound HTMLMediaElement's playbackRate is set live as the slider moves, and because preservesPitch defaults to true the pitch stays natural with no processing; flipping preservesPitch to false gives the pitch-follows-speed (nightcore/vaporwave) mode. A waveform is drawn from decodeAudioData with a synced playhead. Export uses a self-hosted single-threaded ffmpeg.wasm engine (bundled core, no CDN): pitch-preserved speed uses a chained atempo filter (each stage clamped 0.5–2.0), pitch-follows-speed uses asetrate+aresample, and an independent semitone pitch shift uses asetrate→aresample→atempo. Output defaults to the source format across MP3/WAV/FLAC/OGG/M4A.

  • Runs client-side — the audio is never uploaded
  • Self-hosted ffmpeg core (bundled) — no CDN
  • Instant zero-encode preview via playbackRate + preservesPitch
  • Pitch-preserved (atempo) or pitch-follows-speed (asetrate)
  • Independent semitone pitch shift; nightcore/slowed presets
  • MP3/WAV/FLAC/OGG/M4A export, defaulting to source format
Privacy & Security

Privacy vs Cloud Speed Changers

123apps, AudioAlter (~50 MB cap), AudioSpeedChanger, Clideo and VEED (watermark) upload your file and re-encode on a server, so you wait per change. AnyTool runs on the device with a bundled engine: the speed is audible the instant you drag the slider, files never leave the browser, and there is no size cap, watermark or sign-up. It serves both the pitch-preserved practice/podcast use case and the nightcore/slowed content use case in one tool.

Audio speed change: AnyTool vs typical tools
CapabilityAnyToolTypical tools
Data handlingIn your browserOften uploaded
Live previewInstant (no encode)Re-encode per change
Pitch modesPreserved + follows speedUsually one
Semitone pitchYes (independent)Rare
Watermark / capNoneCommon

AnyTool is a privacy-first client-side speed changer — processing runs locally and nothing is uploaded.