Video Bitrate & File Size Calculator
Work out how big a video file will be from its bitrate and length, or which bitrate fits a size limit such as a 25 MB or 2 GB upload cap. Add audio bitrate and your upload speed to see how long the upload takes.
Frequently asked questions
How is the file size calculated?
Total bitrate (video + audio) in bits per second × length in seconds ÷ 8 gives bytes. A 10-minute video at 8 Mbps video and 192 kbps audio is 8.192 Mbps × 600 s ÷ 8 = 614.4 MB. Decimal units are used, as encoders and upload limits use them.
Why does Windows show a smaller number?
Windows counts in binary units: its "GB" is 1,073,741,824 bytes (a GiB), about 7 % more than a decimal GB, so the same file shows a smaller number. The result also gives GiB.
Will my file be exactly this size?
Close, not exact. The container (MP4, MKV) adds about 1–2 %, and most encoders vary the bitrate from scene to scene, so the average lands near the target. Use a two-pass encode and leave a small margin under a hard size limit.
What bitrate should I use?
As a rough guide for H.264: 720p30 about 5 Mbps, 1080p30 about 8 Mbps, 1080p60 about 12 Mbps and 4K30 about 35–45 Mbps. H.265 and AV1 need roughly half for the same quality. Fast motion needs more than talking heads.