Audio Bitrate Calculator
Work out audio sizes and bitrates precisely. Calculate how large a file of a given bitrate and length will be, find the average bitrate of an existing file from its size and duration, or compute the uncompressed bitrate of WAV/PCM audio from sample rate, bit depth and channels. Sizes for common MP3, AAC and Opus settings are shown side by side.
- Runs in your browser
- No sign-up
- Free to use
Seconds or m:ss / h:mm:ss.
Sizes use 1 MB = 1,000,000 bytes. Container overhead and embedded cover art add a little to real files.
How to use Audio Bitrate Calculator
- Choose what to calculate.
- Enter bitrate, duration or file size.
- For uncompressed audio, choose sample rate, bit depth and channels.
- Read the result and the formula.
Audio Bitrate Calculator features
File size
From bitrate and duration.
Average bitrate
From file size and duration.
PCM bitrate
Sample rate × bit depth × channels.
Common settings
MP3, AAC and Opus side by side.
FLAC estimate
Typical lossless size.
Private
Runs in your browser; nothing is uploaded.
When to use Audio Bitrate Calculator
- Planning podcast and audiobook file sizes.
- Checking hosting and bandwidth needs.
- Choosing export settings.
- Understanding WAV and FLAC storage needs.
Audio Bitrate Calculator FAQ
How is file size calculated?
Size = bitrate × duration ÷ 8. 192 kbps for 4 minutes is 192,000 × 240 ÷ 8 = 5.76 MB.
Why is my real file slightly larger?
Containers add headers and metadata, and embedded cover art can add hundreds of kilobytes.
What bitrate is CD audio?
44,100 samples × 16 bits × 2 channels = 1,411.2 kbps.
Which bitrate should I choose?
Speech podcasts: 64–96 kbps mono or 96–128 kbps stereo AAC/MP3. Music: 192–256 kbps AAC or MP3, or 128–160 kbps Opus.
Which megabyte is used?
Decimal: 1 MB = 1,000,000 bytes, as most players and hosting services use.
Bitrate, size and quality
Audio bitrate is the amount of data per second, usually given in kilobits per second (kbps). For compressed formats like MP3, AAC and Opus, it is chosen when encoding and directly determines the file size: double the bitrate, double the size. Uncompressed audio has a bitrate fixed by its format.
File size follows from simple arithmetic: bitrate times duration, divided by eight to convert bits to bytes. A one-hour podcast at 128 kbps takes about 57.6 MB; at 64 kbps half that. The calculator shows the size for your bitrate and, for comparison, for the most common settings.
The reverse calculation tells you the average bitrate of a file you already have, which is useful for variable-bitrate files where players show only an estimate.
Uncompressed PCM audio, as in WAV files, uses sample rate × bit depth × channels. CD quality is 1,411.2 kbps, about 10 MB per minute; 24-bit 96 kHz studio audio is more than three times that. Lossless FLAC typically reduces this by 40–50%, while lossy formats reduce it by 80–95%.
All calculations are exact and run in your browser.