Change Audio Speed

Change audio speed without shifting pitch

Make a recording slower for practice or faster for review. This tool changes the audio stored in a new file, so the speed change travels with your download. It uses time stretching to keep the original pitch instead of changing the sample rate to make voices sound higher or lower.

How to slow down or speed up audio

1. Choose an MP3 or uncompressed PCM WAV between one second and ten minutes, up to 30 MiB.
2. Set a multiplier from 0.5 to 2.0. Below 1 slows down the recording; above 1 speeds it up.
3. Compare the expected duration and choose MP3 or 16-bit PCM WAV.
4. Create the audio, compare the original and result, then download.

Speed and duration

Expected duration is the original duration divided by your multiplier. A 60-second recording becomes about 120 seconds at 0.5×, 80 seconds at 0.75×, 48 seconds at 1.25× or 30 seconds at 2×. Processing boundaries and MP3 encoder padding can cause small differences; check the actual exported duration. Existing pauses are stretched along with the sound.

Keeping pitch does not mean identical sound

Time stretching rearranges small portions of the waveform. The intended musical notes and voice pitch stay the same, but rapid attacks, percussion, sustained textures and speech can acquire artifacts. Try a modest change before using the extremes. This is not a pitch shifter, key changer, beat detector or automatic tempo matcher.

At 1×, the speed filter is bypassed, but export still decodes and encodes the file. WAV remains 16-bit PCM, and sample rates other than 48 kHz are converted to 44.1 kHz. MP3 export is lossy. Keep the original if you only want temporary faster playback in your usual media player.

Choose an export format

Slower audio is longer and normally uses more storage at the same encoding settings. Faster audio is shorter. The estimate describes the audio payload; the finished result shows actual bytes and duration. WAV can be substantially larger than MP3 and does not restore detail lost in the source. Read the MP3 bitrate guide or use the file size calculator to plan storage.

Speed adjustment questions

Is pitch preservation optional?

This page always uses pitch-preserving speed adjustment. It does not offer the tape-style effect where changing speed also changes pitch. Compare sustained notes and speech in the original and processed players before saving.

Can I change only part of a recording?

The multiplier applies to the whole selected file. Use Trim Audio first to export a section. You can then change its speed and use Merge Audio to build a sequence. Each separate MP3 export adds a lossy encoding pass, so use WAV between edits when appropriate.

Does this work with phone recordings?

This tool accepts MP3 and PCM WAV, with mono or stereo channels. For AAC or ALAC M4A, use M4A to MP3 first. That extra conversion is lossy; keep the phone original. Video and surround files are not supported here.

Will this change the volume?

No intentional gain is applied, but stretching and encoding can alter peaks and perceived loudness. Listen at a comfortable level. For a deliberate level change, use audio volume adjustment.

Are recordings uploaded?

No. Processing runs in your browser after loading the local engine. Long slowdowns use more processing time and memory. If the operation fails, try a shorter source or a speed closer to 1×. Cancel stops the current task; you can retry using the original file.

Read the audio speed guide or browse all audio tools.

To transpose notes while keeping the pace, use the audio pitch changer.