Audio Bitrate Calculator
Find out how big an audio file will be from its bitrate and length, how much space uncompressed WAV needs, or which bitrate fits a target size. Everything is calculated instantly in your browser.
Same duration in other formats
| Format | Bitrate | File size | Per minute |
|---|
MB = 1,000,000 bytes (decimal, as used by drive makers and macOS). MiB = 1,048,576 bytes (binary, shown as "MB" by Windows). Lossy and FLAC sizes are estimates; tags and cover art add a little extra.
How to use the Audio Bitrate Calculator
- Pick a mode: File size from bitrate, Uncompressed PCM/WAV, or Bitrate for a target size.
- Enter the duration in hours, minutes and seconds, and the number of tracks if you are sizing several files.
- Choose a preset such as MP3 320 kbps or CD WAV, or type your own bitrate, sample rate, bit depth and channels.
- Press Calculate (results also update as you type) and read the size in MB, MiB and bytes.
- Compare formats in the table below the result, or copy the result to paste it elsewhere.
Audio file size formulas
Bitrate is the amount of data per second of audio. Because there are 8 bits in a byte, the size of a file is simply:
- File size (bytes) = bitrate (bits per second) × duration (seconds) ÷ 8
- Uncompressed PCM bitrate (bps) = sample rate (Hz) × bit depth (bits) × channels
- Bitrate for a target size (bps) = target size (bytes) × 8 ÷ duration (seconds)
Worked example: a 3 minute 30 second song encoded as a 320 kbps MP3 is 320,000 × 210 ÷ 8 = 8,400,000 bytes, which is 8.4 MB or 8.01 MiB. The same song as CD-quality WAV is 44,100 × 16 × 2 = 1,411,200 bps, so 1,411,200 × 210 ÷ 8 = 37,044,000 bytes (about 37 MB), 4.4 times larger.
Size per minute and per hour
| Format | Bitrate | Per minute | Per hour |
|---|---|---|---|
| MP3 / AAC voice | 64 kbps | 0.48 MB | 28.8 MB |
| MP3 standard | 128 kbps | 0.96 MB | 57.6 MB |
| MP3 high | 192 kbps | 1.44 MB | 86.4 MB |
| AAC high | 256 kbps | 1.92 MB | 115.2 MB |
| MP3 maximum | 320 kbps | 2.4 MB | 144 MB |
| WAV 16-bit / 44.1 kHz stereo (CD) | 1,411.2 kbps | 10.58 MB | 635 MB |
| WAV 24-bit / 48 kHz stereo | 2,304 kbps | 17.28 MB | 1.04 GB |
| WAV 24-bit / 96 kHz stereo | 4,608 kbps | 34.56 MB | 2.07 GB |
| WAV 24-bit / 192 kHz stereo | 9,216 kbps | 69.12 MB | 4.15 GB |
An 80-minute audio CD holds 44,100 × 16 × 2 × 4,800 ÷ 8 ≈ 847 MB of raw audio. That is more than the "700 MB" printed on a CD-R because audio CDs use a mode with less error-correction overhead than data CDs.
Choosing a bitrate
- Speech and podcasts: 64–96 kbps mono or 96–128 kbps stereo MP3/AAC is plenty. Opus sounds good for voice from about 24–32 kbps.
- Music for streaming or phones: 128–192 kbps AAC or 192–256 kbps MP3 is transparent for most listeners on most gear.
- Archiving and DJ use: 320 kbps MP3 is the format's ceiling; for a true master copy use FLAC or WAV.
- Recording and editing: 24-bit at 48 kHz is the common studio and video standard. It gives headroom for editing, then you can export a smaller file at the end.
Converting a low-bitrate file to a higher bitrate makes it bigger but never better. To convert files, try the WAV to MP3 or MP3 to WAV converter, and for video sizes use the Video File Size Calculator.
Frequently asked questions
How do you calculate audio file size from bitrate?
File size in bytes = bitrate in bits per second × duration in seconds ÷ 8. For example, a 3:30 song at 320 kbps is 320,000 × 210 ÷ 8 = 8,400,000 bytes, which is 8.4 MB (about 8.01 MiB). Metadata such as cover art adds a little on top.
How big is a WAV file per minute?
CD-quality WAV (44.1 kHz, 16-bit, stereo) runs at 1,411.2 kbps, which is about 10.58 MB per minute or 635 MB per hour. A 24-bit/48 kHz stereo WAV is about 17.28 MB per minute and 24-bit/96 kHz is about 34.56 MB per minute.
How do I calculate the bitrate of uncompressed audio?
Multiply sample rate × bit depth × number of channels. 44,100 × 16 × 2 = 1,411,200 bits per second (1,411.2 kbps). The WAV file adds a header of about 44 bytes, which is negligible for any real recording.
Why does my computer show a smaller number than this calculator?
This calculator shows decimal megabytes (1 MB = 1,000,000 bytes), the unit used by drive makers and macOS. Windows reports binary units (1 MiB = 1,048,576 bytes) but labels them MB, so the same file looks about 4.6% smaller there. Both values are shown.
What bitrate do I need to fit audio into a certain size?
Use the Bitrate for a target size mode. Bitrate (bps) = target size in bytes × 8 ÷ duration in seconds. For a 60-minute podcast that must stay under 50 MB, the maximum is about 111 kbps, so 96 kbps MP3 or AAC is a safe choice.
Are VBR files the same size as this calculation?
For variable bitrate (VBR) files, enter the average bitrate. The real size varies with the material: quiet or simple passages use fewer bits and dense music uses more, so treat the result as an estimate. Constant bitrate (CBR) files match the formula almost exactly.
How big is a FLAC file compared with WAV?
FLAC is lossless but compressed, and typically ends up at roughly 50–70% of the WAV size, depending on the music. CD-quality FLAC usually averages somewhere around 700–1,000 kbps; quiet acoustic recordings compress more than loud, dense rock or electronic tracks.