File size is bitrate made visible, and the math is exact enough to catch lies. A 4-minute song labeled 320kbps that weighs 4MB is not 320kbps. Use this table to sanity-check any download.
| Bitrate | Per minute | 3-minute song | 4-minute song | 1-hour podcast |
|---|---|---|---|---|
| 96 kbps | ~0.7 MB | ~2.2 MB | ~2.9 MB | ~43 MB |
| 128 kbps | ~1.0 MB | ~2.9 MB | ~3.8 MB | ~58 MB |
| 160 kbps | ~1.2 MB | ~3.6 MB | ~4.8 MB | ~72 MB |
| 192 kbps | ~1.4 MB | ~4.3 MB | ~5.8 MB | ~86 MB |
| 256 kbps | ~1.9 MB | ~5.8 MB | ~7.7 MB | ~115 MB |
| 320 kbps | ~2.3 MB | ~7.0 MB | ~9.3 MB | ~144 MB |
Bitrate is kilobits per second. Multiply by 60 seconds and divide by 8 (bits per byte): 128kbps becomes 960 kilobytes per minute, about 1MB. Container overhead adds a few percent. Variable-bitrate (VBR) files vary around these numbers; constant-bitrate (CBR) files land almost exactly on them.
This is the same verification method from is 320kbps from YouTube real, applied to any file.
Because the source caps the content. A YouTube video's audio tops out near 160kbps Opus, so even a file encoded at 320kbps carries only ~160kbps of genuine detail. The file will be 320kbps-sized but 160kbps-substanced. See what bitrate YouTube audio really is.
About 1MB. 128 kilobits per second times 60 seconds is 960 kilobytes, plus small container overhead.
About 9.3MB. At 320 kilobits per second, each minute is roughly 2.3MB.
Yes. A 4-minute file labeled 320kbps weighing 4MB cannot be 320kbps; the math does not allow it. Compare any file against the size table.