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.
Selected audio is processed locally by this tool; the audio pipeline does not send it to an upload API.
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.