Audio Bitrate Calculator
Calculate audio bitrate from file size and duration.
Understanding Audio Bitrate
Audio bitrate determines the quality and file size of digital audio. It measures how many bits of data are processed per second, typically expressed in kilobits per second (kbps). Higher bitrates generally mean better audio quality but larger file sizes.
Audio Bitrate Quality Standards
| Quality Level | Bitrate Range | Use Case | File Size (1 hour) |
|---|---|---|---|
| Low Quality | 32-64 kbps | Voice calls, voice memos | 14-28 MB |
| Acceptable | 96 kbps | Podcasts, audiobooks, speech | 42 MB |
| Good | 128 kbps | Standard music streaming, FM radio quality | 56 MB |
| High Quality | 192 kbps | Music downloads, CD-like quality | 84 MB |
| Very High Quality | 256 kbps | Premium music streaming | 112 MB |
| Studio Quality | 320 kbps | Professional audio, archival | 140 MB |
| Lossless | 700-1,400 kbps | FLAC, ALAC, uncompressed audio | 300-600 MB |
Common Audio Formats and Bitrates
- MP3: 128-320 kbps (most compatible)
- AAC: 96-256 kbps (better quality than MP3)
- OGG Vorbis: 96-256 kbps (open source)
- Opus: 64-192 kbps (modern, efficient)
- FLAC: 700-1,000 kbps (free, open)
- ALAC: 700-1,000 kbps (Apple)
- WAV: 1,411 kbps (uncompressed)
- AIFF: 1,411 kbps (uncompressed)
Bitrate Calculation Formula
Bitrate (kbps) = (File Size in KB × 8) / Duration in seconds
Example: A 5 MB file that's 3 minutes (180 seconds) long:
5,120 KB × 8 / 180 = 227 kbps
Streaming Service Bitrates
| Service | Standard | High Quality | Lossless |
|---|---|---|---|
| Spotify | 96 kbps | 160 kbps | 320 kbps (Premium) |
| Apple Music | 128 kbps | 256 kbps (AAC) | ALAC Lossless |
| YouTube Music | 128 kbps | 256 kbps | - |
| Amazon Music | 128 kbps | 256 kbps | HD Lossless |
| Tidal | 160 kbps | 320 kbps | FLAC (HiFi) |
Factors Affecting Audio Bitrate Choice
- Content Type: Music needs higher bitrates than speech/podcasts
- Playback Device: High-end audio systems benefit from higher bitrates
- Storage Limitations: Mobile devices may require compressed formats
- Bandwidth: Streaming requires balance between quality and data usage
- Codec Efficiency: Modern codecs (AAC, Opus) sound better at lower bitrates
Podcast Production Guidelines
For podcast production, consider these bitrate recommendations:
- Solo voice: 64 kbps mono is sufficient
- Interview/multiple voices: 96 kbps mono or 128 kbps stereo
- Music content: 128-192 kbps stereo
- High production: 192-256 kbps stereo
Sample Rate and Bit Depth
In addition to bitrate, audio quality is affected by:
- Sample Rate: 44.1 kHz (CD quality), 48 kHz (video), 96+ kHz (studio)
- Bit Depth: 16-bit (standard), 24-bit (professional), 32-bit (mastering)
- Channels: Mono (1), Stereo (2), Surround (5.1, 7.1)
Variable vs Constant Bitrate
Pros: Predictable file size, better compatibility, streaming-friendly
Cons: Less efficient, may waste bits on simple passages
Pros: Better quality per file size, efficient compression
Cons: Unpredictable size, may have compatibility issues
Quick Reference
Common Bitrates:
- 64 kbps: Voice only
- 96 kbps: Podcasts
- 128 kbps: Music (min)
- 192 kbps: High quality
- 256 kbps: Premium
- 320 kbps: Maximum MP3
File Size Guide
1 Hour of Audio:
- 64 kbps: 28 MB
- 128 kbps: 56 MB
- 192 kbps: 84 MB
- 256 kbps: 112 MB
- 320 kbps: 140 MB