Practical focus
Use this calculator to estimate what bitrate is needed for a target file size and duration before compressing.
Private browser-based audio compression
Audio Bitrate Calculator
Calculate audio bitrate from duration and target MB so you can choose realistic compression settings.
Your audio is compressed locally in your browser. Files are not uploaded to a server.
MP3 / WAV / M4A / AAC / OGG / FLAC inputMP3M4A / AACOGG
Recommended bitrate-
Estimated file size-
Quick tips
- Formula: bitrate kbps ~= target size MB x 8192 / duration seconds.
- The result is an estimate, not a guarantee.
- Voice, podcast, and music need different quality ranges.
How to use
- Enter the audio duration and the target file size.
- Read the estimated bitrate in kbps.
- Compare the result with practical ranges: 64-96 kbps for voice, 96-128 kbps for podcasts, and 128-192 kbps for music.
- Open a target-size compressor page when you want the tool to apply the estimate.
Recommended settings
| Audio type | Useful bitrate range |
|---|---|
| Voice | 64-96 kbps |
| Podcast | 96-128 kbps |
| Music sharing | 128-192 kbps |
| High-quality copy | 192 kbps or higher |
| Very small voice | 48-64 kbps |
Supported formats
The formula applies to bitrate-based compressed formats such as MP3, AAC, and OGG.
WAV size is usually calculated from sample rate, bit depth, channels, and duration instead of a lossy bitrate target.
Quality vs file size
The estimate uses bitrate kbps ~= target size MB x 8192 / duration seconds.
Actual files can differ because containers, metadata, encoder behavior, and VBR settings add variation.
Privacy and local processing
The calculator does not need to upload audio; it only uses the numbers you enter.
If you later compress a file, that processing also runs locally in the browser.
Things to watch
- If the calculated bitrate is below about 32 kbps, the target is probably too small for most content.
- A high calculated bitrate may mean the target size is larger than you need.
FAQ
How do I calculate audio bitrate?
Use bitrate kbps ~= target size MB x 8192 / duration seconds.
Why is the result only an estimate?
Container overhead, metadata, VBR behavior, and encoder settings can change the final size.
What bitrate is good for voice?
64-96 kbps is a practical range for most spoken audio.
What bitrate is good for music?
128-192 kbps is a common sharing range; use higher when quality matters.
How do I choose bitrate for a target file size?
Calculate the bitrate from duration and target MB, then check whether it is realistic for the content type.