DataCalc
Bitrate ↔︎ File Size Calculator
Professional video bitrate calculator. Calculate optimal bitrate settings, estimate file sizes, and determine video quality for streaming and encoding.
How this calculator works
The Bitrate ↔︎ File Size calculator converts between data rate, duration, and file size. Use it to work out what a given bitrate produces on disk, or to find the bitrate that fits a delivery size limit — a daily task in streaming encoding, review uploads, and deliverable specs.
Bitrate is measured in megabits per second (Mb/s), while files are measured in bytes — the constant 8 bits per byte is where most back-of-napkin math goes wrong. This tool keeps the units straight for you.
The bitrate ↔ size relationship
File Size (GB) = Bitrate (Mb/s) × Duration (s) ÷ 8,000 — Bitrate (Mb/s) = File Size (GB) × 8,000 ÷ Duration (s)
Example: to fit a 90-minute film in 4 GB → 4 × 8,000 ÷ 5,400 ≈ 5.9 Mb/s.
| Bitrate | Per minute | Per hour |
|---|---|---|
| 10 Mb/s | 75 MB | 4.5 GB |
| 25 Mb/s | 187.5 MB | 11.25 GB |
| 50 Mb/s | 375 MB | 22.5 GB |
| 100 Mb/s | 750 MB | 45 GB |
| 250 Mb/s | 1.87 GB | 112.5 GB |
| 500 Mb/s | 3.75 GB | 225 GB |
Frequently asked questions
What bitrate should I use for 4K uploads?
For 4K SDR uploads at standard frame rates, platforms like YouTube recommend roughly 35–45 Mb/s (more for HDR or high frame rate). Uploading at higher quality than the recommendation is fine — the platform re-encodes everything anyway.
What is the difference between Mbps and MB/s?
Mb/s (megabits per second) is 8× smaller than MB/s (megabytes per second). A 400 Mb/s codec writes 50 MB every second. Network and codec specs use bits; file sizes and drive speeds usually use bytes.
CBR or VBR — which should I use?
Constant bitrate (CBR) gives predictable file sizes and is often required for broadcast delivery. Variable bitrate (VBR) puts data where the picture needs it and looks better at the same average rate — it is the default for streaming and web delivery.
Does higher bitrate always mean better quality?
Only up to a point. Past the rate a codec needs for the content, extra bits are wasted. A well-encoded H.265 file can match an H.264 file at roughly half the bitrate, so codec choice matters as much as raw rate.
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