Audio File Size Calculator
Calculate audio file size from track duration, sample rate (44.1-192 kHz), bit depth, and channels.
Compares WAV, lossless FLAC, and lossy MP3 and AAC sizes.
Audio file size is determined by three factors: bit rate, sample rate, channel count, and duration. Understanding this calculation is essential for storage planning, streaming budget estimation, and format selection in music production and distribution.
Uncompressed audio (WAV/AIFF) formula: File Size (bytes) = Sample Rate × Bit Depth × Channels × Duration (seconds) ÷ 8
Divide by 8 to convert bits to bytes.
Where:
- Sample Rate = samples per second (Hz). Common: 44,100 Hz (CD quality), 48,000 Hz (video), 96,000 Hz (studio)
- Bit Depth = bits per sample. Common: 16-bit (CD), 24-bit (professional), 32-bit float (editing)
- Channels = 1 (mono), 2 (stereo), 6 (5.1 surround)
- Duration = length in seconds
Compressed audio (MP3/AAC) formula: File Size (bytes) = Bit Rate (bps) × Duration (seconds) ÷ 8
Common MP3 bit rates and quality:
| Bit Rate | Quality | Size per Minute |
|---|---|---|
| 128 kbps | Acceptable (streaming) | ~960 KB |
| 192 kbps | Good (most listeners) | ~1.44 MB |
| 256 kbps | Very good (audiophile) | ~1.92 MB |
| 320 kbps | Excellent (near-lossless) | ~2.40 MB |
Uncompressed reference:
- CD quality (44.1 kHz, 16-bit, stereo): 10.1 MB per minute
- Studio quality (96 kHz, 24-bit, stereo): 34.6 MB per minute
Worked example: A 4-minute song at CD quality WAV: Size = 44,100 × 16 × 2 × 240 / 8 = 338,688,000 bytes = ~338 MB
Same song as 320 kbps MP3: Size = 320,000 × 240 / 8 = 9,600,000 bytes = ~9.6 MB
Compression ratio: 338 / 9.6 = 35:1 — MP3 achieves 35× size reduction with minimal perceptible quality loss at 320 kbps.
Streaming data usage: 1 hour of Spotify (320 kbps) = ~144 MB/hour. Lossless (Apple Lossless ALAC at 1,411 kbps) = ~635 MB/hour.