Video file size calculator
How big a video file will be from its bitrate and length.
File size
Rounded for displayFile size: ≈ 2.31 GB
- Megabytes
- 2,307.6 MB
- Gibibytes
- ≈ 2.15 GiB
- Mebibytes
- ≈ 2,200.7 MiB
How it works
A bitrate is the amount of data per second. Adding the video and audio bitrates and multiplying by the duration in seconds gives the total bits; dividing by 8 gives bytes.
The result assumes a constant bitrate. Variable-bitrate files average out close to their stated rate, and container overhead usually adds only about 1–2%.
GB and MB here are decimal (10⁹ and 10⁶ bytes); GiB and MiB are binary (1,024³ and 1,024² bytes).
Formula
Size (bytes) = (video bit/s + audio bit/s) × seconds ÷ 8
Worked example
One hour of 5 Mbit/s video with 128 kbit/s audio is (5,000,000 + 128,000) × 3,600 ÷ 8 = 2,307,600,000 bytes: 2,307.6 MB, or 2.31 GB.
Questions people ask
How much data does an hour of HD streaming use?
At a typical 5 Mbit/s, about 2.3 GB an hour. Higher-quality 4K streams at 15–25 Mbit/s use roughly 7 to 11 GB an hour.
Why is the file a little larger than calculated?
Containers such as MP4 add headers and index data, and variable-bitrate encoding can run above the average in places.