Video size is easier to reason about when you think in bits per second. A video that averages 4 megabits per second for one minute uses roughly 30 megabytes before container overhead: 4 Mb/s × 60 seconds ÷ 8 bits per byte ≈ 30 MB.
A quick file-size estimate
Total bitrate includes video plus audio. For example, a 2.5 Mb/s video stream with 0.1 Mb/s audio is about 2.6 Mb/s total. Real files can vary because encoders do not always hit an average bitrate perfectly.
Resolution does not directly set the size, but it changes what bitrate looks acceptable
A 1920 × 1080 video and a 1280 × 720 video can theoretically use the same bitrate. The 720p version has fewer pixels competing for those bits and may therefore look cleaner at a tight target. Motion and scene complexity matter too: a talking head against a plain wall compresses more easily than leaves, water, confetti, or fast camera movement.
| Target | 60-second approximate total bitrate | What it implies |
|---|---|---|
| 10 MB | ~1.33 Mb/s | Very constrained for 1080p; may suit simpler or lower-resolution content |
| 25 MB | ~3.33 Mb/s | More practical for short social clips |
| 50 MB | ~6.67 Mb/s | Allows substantially more detail |
| 100 MB | ~13.3 Mb/s | High headroom for a one-minute clip |
How Fitabyte uses the target
For supported browser media, Fitabyte reads the duration and derives a bitrate budget from the target file size. It reserves part of that budget for audio, encodes the video, checks the result, and can adjust if the first pass is still too large. Extremely small targets are rejected when there are not enough bytes per second to make a sensible playable result.
- Longer duration means fewer bits are available for each second at the same target size.
- Higher motion needs more bitrate to avoid blockiness.
- Audio also consumes part of the target.
- A smaller resolution can improve perceived quality when the bitrate is very tight.
- Browser-based encoding is convenient but can be slower on long or high-resolution files.