Free tool
Audio speed changer
This audio speed changer saves a recording faster or slower, anywhere from half speed to double. Voices keep their natural pitch at the new speed, or untick Keep the pitch to let it rise and fall like a tape. The new length shows as you drag.
- Free
- 0.5× to 2×, pitch kept
- Nothing is uploaded
Drop your audio file here, or Choose your audio file
MP3, M4A, WAV, FLAC, OGG, AAC, or the sound of an MP4, MOV or WebM video, up to 1 GB and 2 hours. Everything happens in your browser; nothing is uploaded.
MP3 encoding by LAME, open-source software.
Listening back to meetings at 2×? In NoteOwl a recording plays beside its transcript at 0.75× to 2×, and any line replays on its own, so you can read instead of listening.
How it works
How do you speed up or slow down audio?
Add the recording, then drag the speed slider or press 1.25×, 1.5× or another preset: the new length appears beside it. Leave Keep the pitch on for natural voices. Listen to eight seconds at the new speed, press Change speed and download the file.
- 1
Add the recording
A lecture, a podcast, an interview to type up or a song to practise with.
- 2
Pick the speed
From 0.5×, half speed, to 2×, double. Below 1× slows it down; above speeds it up.
- 3
Listen and save
The preview uses the same processing as the file. Save it as MP3 to share or WAV to edit.
Does speeding up audio change the pitch?
Only if you want it to. To speed up audio with the pitch kept, the page uses time-stretch: voices go faster or slower but stay at their own pitch. Untick Keep the pitch and it moves with the speed, as when a record spins too fast.
- On
- Length13.3 s
- Pitch440 Hz, unchanged
- Off
- Length13.3 s
- Pitch660 Hz, a fifth higher
| Keep the pitch | Length | Pitch |
|---|---|---|
| On | 13.3 s | 440 Hz, unchanged |
| Off | 13.3 s | 660 Hz, a fifth higher |
How much time does a faster speed save?
The length divides by the speed. An hour-long lecture takes 48 minutes at 1.25×, 40 at 1.5× and 30 at 2×. Slowing down works the other way: at 0.75× a 6:44 podcast became 8:59, which gives you more time to catch each word.
- 0.5×
- An hour becomes2 hours
- Often used forLearning a fast passage of music
- 0.75×
- An hour becomes1 hour 20 minutes
- Often used forTyping up an interview by hand
- 1.25×
- An hour becomes48 minutes
- Often used forLectures and talks
- 1.5×
- An hour becomes40 minutes
- Often used forPodcasts and recorded meetings
- 2×
- An hour becomes30 minutes
- Often used forSkimming for one part
| Speed | An hour becomes | Often used for |
|---|---|---|
| 0.5× | 2 hours | Learning a fast passage of music |
| 0.75× | 1 hour 20 minutes | Typing up an interview by hand |
| 1.25× | 48 minutes | Lectures and talks |
| 1.5× | 40 minutes | Podcasts and recorded meetings |
| 2× | 30 minutes | Skimming for one part |
Does keeping the pitch work in every browser?
Yes, because the page does the time-stretching itself rather than setting the browser player’s playback speed. It cuts the sound into 40 ms pieces and overlaps them at the new spacing, lining each up with the last. Chrome and Safari’s engine gave the same length and pitch.
Which speed is best for speech?
Try the preview at 1.25× and at 1.5×, and keep the faster one you can still follow without effort: it depends on the speaker and the subject. For typing a recording out by hand, 0.75× gives you time to keep up with each sentence.
Is there a faster way to get through a recorded meeting?
Read it. NoteOwl transcribes a recording on your Mac and plays it beside the transcript at 0.75× to 2×; tap any line to hear just that moment. For meetings, it writes a summary with action items, so you may not need to listen at all.
FAQ
Questions about changing audio speed
Is the audio sent anywhere to change its speed?
No. The time-stretching runs in this page, on your device; the recording isn’t uploaded and you don’t sign up. Saving a 6:44 podcast at 0.75× made no network requests at all.
Can I change the speed without changing the pitch?
Yes, that’s what Keep the pitch does, and it’s on by default. A tone at 440 Hz saved at 1.5× was still 440 Hz, while the file became a third shorter.
What speeds can I choose?
Anything from 0.5× to 2× in steps of 0.05, with buttons for 0.75×, 0.9×, 1.1×, 1.25×, 1.5× and 2×. The new length shows beside the slider as you drag.
Can I hear it before saving?
Yes. Listen at the chosen speed plays eight seconds of the result from the playhead, made the same way as the file. Click the waveform to choose where it starts.
How long does it take to save?
Seconds for most recordings. A 6:44 podcast slowed to 0.75× was saved as an 8:59 MP3 in about six and a half seconds in Safari’s engine.
Can I change the speed of a song?
Yes. Untick Keep the pitch for the classic sped-up or slowed-down sound, or keep it on to practise along at a slower tempo in the same key.
Keep exploring
More audio editing tools
- Audio trimmerTrim the start and end off a recording in your browser by dragging on its waveform; MP3, M4A, WAV and FLAC are cut without re-encoding
- MP3 cutterCut a clip out of an MP3 or any audio file, with fades, or cut a part out of the middle; saves an MP3 at 128, 192 or 320 kbps
- Audio splitterSplit a long recording into parts in your browser: equal parts, every few minutes or where you choose, each split moved to a pause; no re-encoding
- Audio joinerJoin audio files of any format into one MP3 or WAV in your browser, in the order you set, with a pause or a crossfade between them
Related
- Speech time calculatorHow long a speech takes to say from its word count, at a slow, average or fast pace, and how many words fit in a set time
- Lecture recorderRecord lectures in the room through your Mac’s microphone, in an online class with no bot, or from a file, then turn them into study notes
- Audio to textTranscription software for your Mac: drop in an audio or video file and get a speaker-labelled transcript with timestamps, unlimited, with nothing uploaded
Read the meeting instead of replaying it
Free to download. Runs entirely on your Mac.
macOS 26 or later · Apple Silicon (M1 or newer) · 16 GB memory minimum, 24 GB recommended
About NoteOwl
NoteOwl is private AI meeting notes and memory for the Mac. It captures meetings without a bot joining the call, labels every speaker, writes summaries and action items, and builds a memory of every conversation that you can chat with — fully offline, because the speech recognition and the AI run on the Mac itself. Dictation into any app is free; Pro is a one-time purchase.
NoteOwl pricing: what’s free and what Pro adds
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