How to calculate video file size
Video file size can be estimated from the combined video and audio bitrate and the total duration.
The calculator adds the video bitrate and audio bitrate before multiplying by duration.
Video file size example
A 10-minute video encoded at 8 Mbps with 192 kbps audio has a total bitrate of 8.192 Mbps.
Over 600 seconds, that produces approximately 614.4 MB of data, or about 0.614 GB using decimal storage units.
Calculate bitrate from a target file size
The calculator can also work in reverse. If you know the desired file size and duration, it first calculates the total bitrate available.
The selected audio bitrate is then subtracted from the total bitrate to estimate the video bitrate available for encoding.
Video bitrate vs. audio bitrate
Video bitrate usually accounts for most of the data in a video file, but audio also contributes to the final size.
Enter the video bitrate in Mbps and audio bitrate in kbps. Enter an audio bitrate of zero when estimating a video without an audio track.
Why resolution alone cannot determine video file size
Two videos with the same resolution, frame rate and duration can have very different file sizes when their encoding bitrates differ.
Codec, compression settings, scene complexity and encoder behavior can influence the bitrate required for a given quality level. For that reason, this calculator uses bitrate directly instead of guessing a file size from resolution alone.
MB and GB vs. MiB and GiB
Decimal storage units use powers of 1,000. One MB is 1,000,000 bytes and one GB is 1,000,000,000 bytes.
Binary units use powers of 1,024. One MiB is 1,048,576 bytes and one GiB is 1,073,741,824 bytes.
This calculator reports both systems so you can compare file sizes without treating MB and MiB as identical units.
File size vs. transfer time
Once you know the estimated video file size, you can use the Data Transfer Calculator or Download Time Calculator to estimate how long the file may take to transfer.
For general file-size unit conversions, use the File Size Calculator.
The calculation represents stream data from the entered bitrates. Actual finished files can differ because of container overhead, metadata, variable bitrate behavior and encoder implementation.
Frequently asked questions
How do I calculate video file size from bitrate?
Add the video and audio bitrates, multiply by the duration in seconds, then divide by eight to convert bits to bytes.
Does audio affect video file size?
Yes. Audio contributes data throughout the duration, so its bitrate is included in the total file-size estimate.
Can I calculate a bitrate for a maximum upload size?
Yes. Choose bitrate from target size, enter the duration, target file size and audio bitrate, and the calculator estimates the available video bitrate.
Why is the actual exported file sometimes different?
Containers, metadata, variable bitrate encoding and encoder behavior can cause the actual file size to differ from a simple bitrate-based estimate.
Is 1 GB the same as 1 GiB?
No. A decimal gigabyte is 1,000,000,000 bytes, while a gibibyte is 1,073,741,824 bytes.
Using this calculator effectively
The Video File Size Calculator estimates video storage from duration, video bitrate and audio bitrate. It can also work backward from a target file size to calculate the approximate video bitrate available.
Common uses
- Estimating the storage size of a video before encoding or uploading it.
- Finding a video bitrate that fits a target upload or storage limit.
- Comparing decimal MB and GB with binary MiB and GiB for the same estimated video data.
Tips for a better estimate
- Use the actual or planned encoding bitrate rather than estimating size from resolution alone.
- Include the audio bitrate because audio contributes to the final file size throughout the video duration.
- Allow for container overhead, metadata and variable-bitrate behavior when an exact maximum file size is important.
Related calculations
Audio File Size Calculator · Download Time Calculator · File Size Calculator