Speed & Pitch Changer
Slow down or speed up audio without touching its pitch, shift pitch without touching its speed, or link both together for the classic tape effect — with an instant live preview so you can hear the tempo before spending time on the real export.
Quick Tips for the Best Result
Features
Three Different Problems, Three Separate Modes
"Change the speed" and "change the pitch" sound like they should be one setting, but they're genuinely different problems that call for different tools, which is why this page splits them into three modes instead of a single slider. Change Speed is the one most people actually want when they say "speed changer" — playing audio faster or slower while it still sounds like the same voice or instrument, just moving quicker or slower through the material. Change Pitch flips that: the tempo and timing stay exactly as recorded, only the pitch itself moves, which matters for singers transposing a song into a comfortable range or musicians practicing along at a different key.
Speed + Pitch Together is the odd one out on purpose — it's the classic, simplest effect, the one everyone already knows from playing a cassette or a vinyl record at the wrong speed. Both pitch and tempo move as a single linked pair, which is exactly right for a deliberate creative effect but the wrong choice any time the goal is simply to listen faster or slower without the voice changing character.
Picking the right mode first saves a wasted export, too — running a file through Change Pitch when what you actually wanted was Change Speed produces something that technically works but solves the wrong problem, since duration won't have moved at all. The mode picker sits at the very top of the settings for exactly this reason: get that choice right before touching any slider underneath it.
Why Keeping Pitch Steady Is the Hard Part
Most free "audio speed changer" tools online are really just adjusting playback rate — simple, fast, and the reason sped-up voices always sound a little squeaky and slowed-down ones always sound a little demonic. That happens because playback rate controls how quickly the waveform itself is resampled, and the waveform's shape is literally what determines pitch, so changing one always drags the other along for the ride.
Getting speed and pitch to move independently needs a different approach entirely. Change Speed here uses WSOLA — waveform similarity overlap-add — which works by slicing the audio into small overlapping frames, searching for how each frame should be repositioned so it blends smoothly into its neighbor, and reassembling those frames at new spacing. That changes how long the audio takes to play without ever resampling the waveform's actual shape, which is why the pitch stays put even as the tempo moves. Pitch shifting works as almost the mirror image: the waveform is resampled first (which does move the pitch, as a byproduct also changing duration), and then the same time-stretch technique restores the original duration afterward, since it only affects timing and never touches pitch on its own.
Instant Preview, Then the Real Thing
Because genuine time-stretching takes real processing rather than being instantaneous, this tool adds something most competitors skip entirely — a Live Preview that plays the original file through the browser's own playback-rate engine the moment you move the slider, with zero waiting. It's an approximation rather than the final quality (browsers don't expose fine control over the specific stretching algorithm they use internally), but it's genuinely useful for quickly auditioning several speed values in a row before settling on one and running the actual Apply step.
Once a setting feels right, Apply runs the real WSOLA processing against the whole file and swaps the waveform, playback and predicted duration over to the new version — checkable immediately with Play Current against Play Original before spending any time on exporting. If a longer file's processing takes a few seconds, that's expected: the algorithm works file-by-file, not in real time, which is exactly what keeps a significant slow-down from taking longer to process than the source recording itself.
Who This Actually Helps
Students speed up a recorded lecture to get through it faster without the professor sounding like a cartoon character. Language learners slow down a native-speaker clip enough to catch every syllable clearly, without the voice dropping into an unintelligible low rumble. Musicians shift a song's key with Change Pitch to match their vocal range, or slow down a solo with Change Speed to learn it note by note at a manageable tempo. Podcasters occasionally reach for the classic linked mode deliberately, for a stylized sound effect rather than a clean, natural-sounding adjustment.
Someone learning guitar slows a solo down to 0.6× with Change Speed to work out the fingering, then once it's under control, trims just that section out with the Audio Trimmer & Cutter to practice it on a loop. A podcaster preparing a highlight reel speeds several clips up slightly to tighten the pacing, then evens out the loudness across them afterward with the Volume Booster & Normalizer before combining them.
What This Can't Do Perfectly
Time-stretching and pitch-shifting are both approximations, not lossless transformations — pushing either one toward the edges of the available range (well below 1× or above 2×, or a full octave of pitch shift) starts to introduce a subtle smearing or warble on complex material, which is a property of the underlying math rather than something specific to this implementation. It's the same tradeoff every time-stretching algorithm makes, including the ones built into professional desktop audio software.
It also isn't a substitute for actually re-recording something at the tempo or key you wanted from the start — a rushed, sloppy performance sped up or slowed down is still a rushed, sloppy performance, just at a different pace. For anything beyond speed and pitch — trimming, merging multiple takes, or cleaning up dead air first — the Silence Remover and the other tools in this category handle those jobs separately, so each step stays focused on one thing done well.
And it's worth remembering the Change Pitch and Change Speed modes aren't quite mirror images of each other in how they're built — pitch shifting resamples the file first and then time-stretches it back to length, so it inherits both steps' processing time, while a pure speed change only needs the one pass. Neither takes long for a typical few-minute file, but it explains why applying a large pitch shift on a long recording can feel a touch slower than an equivalent speed change on the same file.