Video File Size Calculator
Estimate how big a video file will be from its video and audio bitrates and its length, in MB and GB, and how much space each minute takes.
Roughly 5 to 8 Mbps for 1080p, 35 to 45 Mbps for 4K on YouTube-style uploads.
File size
2.76 GB
- In MB
- 2,764.8 MB
- Per minute
- 61.44 MB
45 minutes at 8 Mbps makes a file of about 2.76 GB.
How it's worked out
- Total bitrate
8 Mbps + 192 kbps8.192 Mbps - Size
bitrate × 2,700 s ÷ 8 bits a byte2,765 MB
- Variable-bitrate files can come out smaller or larger than this average. Sizes use 1 GB = 1,000 MB, as drives and phones show.
The formula
Size (bytes) = (video bitrate + audio bitrate) × seconds ÷ 8
Example
A 45-minute video at 8 Mbps with 192 kbps audio is (8,000,000 + 192,000) × 2,700 ÷ 8 = 2,764.8 MB, about 2.76 GB, or 61 MB a minute.
Sizes use 1 GB = 1,000 MB, as phones and drives display them.
Questions people ask
How is video file size worked out?
Total bitrate × length in seconds ÷ 8 gives the size in bytes. 8 Mbps for 45 minutes with 192 kbps audio is about 2.76 GB.
What bitrate should I use?
As a rough guide, 5 to 8 Mbps for 1080p and 35 to 45 Mbps for 4K. Higher frame rates need more.
Why is my file a different size?
Most encoders use a variable bitrate, so simple scenes take less and busy scenes take more than the average.
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem