At a glance
- Cost
- 100% free, no account
- MP3 bitrate
- From 32 to 160 kbps
- Stereo or mono
- Your choice
- Sample rate options
- 44.1, 32, 22.05 and 16 kHz
- Saves as
- MP3
- Before you start
- Live estimate of the new file size
Shrinking a file
- Open the file that's too big.
- Choose a preset (High quality, Balanced, Small or Smallest) and watch the size estimate update.
- Tweak if you like: bitrate, mono or stereo, and sample rate.
- Compress and check the result in the player before downloading. The saving is shown next to the file.
The three levers of file size
Bitrate
Data per second of audio. Halve it and the file roughly halves. The biggest single saving.
Channels
Mono merges left and right. For speech you won't hear a difference, and quality per kilobyte improves.
Sample rate
Lower rates trim the highest frequencies. 22 kHz or 16 kHz is plenty for voice and keeps low bitrates clean.
Quick guide to presets
| Preset | What it does | Typical use | 1 hour ≈ |
|---|---|---|---|
| High quality | 128 kbps, channels kept | Music you still want to enjoy | 58 MB |
| Balanced | 96 kbps, channels kept | Demos, mixed content | 43 MB |
| Small | 64 kbps mono | Podcasts, lectures, interviews | 29 MB |
| Smallest | 32 kbps mono, 22 kHz | Voice notes, strict attachment limits | 14 MB |
For reference, Gmail and Outlook allow about 20–25 MB per email. Always preview the result, because the right setting is the lowest one that still sounds acceptable for its purpose.
Common questions
How much smaller can my file get?
It depends on the source. A WAV can often shrink by 95% or more. An MP3 that's already compressed may shrink by 30–80% depending on the settings.
Will it sound worse?
Some quality is always traded for size. Speech tolerates heavy compression very well; music needs higher settings.
Is this the same as a dynamic range compressor?
No. This tool reduces file size. To make quiet audio louder, use the Volume Booster.
Where is my file processed?
In your own browser. Nothing is uploaded.