Video Bitrate Calculator
File size is (video kbps + audio kbps) x 1000 x seconds / 8 bytes. A 10-minute video at 5,000 kbps video and 128 kbps audio comes to about 384.6 MB, where 1 MB is 1,000,000 bytes.
How to use
- Choose File size to find the size of a video, or Bitrate for a size limit to find the bitrate that fits.
- Enter the length in hours, minutes and seconds, and the audio bitrate. For file size, enter the video bitrate too. For a size limit, enter the maximum size and pick MB or MiB.
- Read the result. Add a container overhead of 1 to 2 percent if you want a safety margin under a limit.
How it works
File size in bytes = (video kbps + audio kbps) × 1000 × seconds ÷ 8. One kbps is 1,000 bits per second.
For a size limit, the total bitrate = size × 8 ÷ seconds, and the video bitrate is that minus the audio bitrate. If the audio alone already uses the whole budget, the calculator reports an error.
MB means 1,000,000 bytes and MiB means 1,048,576 bytes, so the same file looks about 5% smaller in MiB. Check which one your upload limit uses and pick the matching unit. Enter the limit in whichever unit the site states.
Real files carry container data and variable bitrate encoders land near the target and not exactly on it. The overhead field adds a percentage on top, so use a margin when you must stay under a hard limit.
FAQ
What video bitrate fits a 10-minute clip into 25 MB?
With 128 kbps audio, 25 MB over 600 seconds allows 333 kbps in total, so about 205 kbps for video. That is low, so expect a small resolution.
How big is a 1-hour video at 5 Mbps?
About 2.25 GB with no audio. Add 128 kbps audio and it is roughly 2.31 GB.
Should I use MB or MiB for the limit?
Use the unit the service states. If you are unsure, pick MB, which is smaller than MiB, so the result stays safely under the limit.
Does the calculator choose a codec or resolution?
No. It only does the arithmetic between bitrate, length and size. A modern codec such as H.265 or AV1 looks better than H.264 at the same bitrate.