How to estimate video file size before exporting
A video’s file size depends primarily on its duration and the amount of data encoded each second. Video bitrate is usually the largest part of the total, but an audio track and the file container also contribute. This calculator uses the duration and the video and audio bitrate values from your export settings to estimate how much storage the finished file may need.
You do not need to upload a video. Enter the planned duration, video bitrate in megabits per second (Mbps), and audio bitrate in kilobits per second (kbps). The estimate updates in your browser as you change the values.
The video file size formula
Convert audio bitrate from kbps to Mbps before adding it to video bitrate. Then multiply the combined megabits per second by the number of seconds and divide by eight to convert bits to bytes. This calculator reports decimal units: 1 MB = 1,000,000 bytes and 1 GB = 1,000,000,000 bytes.
Worked example: a one-minute video
Suppose your export is 60 seconds long, with video at 8 Mbps and audio at 192 kbps. Audio at 192 kbps equals 0.192 Mbps, so the combined bitrate is 8.192 Mbps.
Use the result as a planning estimate, not an exact prediction of a saved file. The actual output may differ because of variable bitrate, container metadata, multiple audio tracks, subtitles, and other streams that are not included in the inputs.
What changes a video’s file size?
- Duration: at the same average bitrate, a video twice as long needs roughly twice as much encoded data.
- Video bitrate: higher bitrate usually increases file size and gives the encoder more data to represent detail, though quality also depends on codec and footage.
- Audio bitrate: audio adds to the total, although it is often much smaller than the video stream.
- Encoding mode: variable-bitrate encoding changes the amount of data across scenes, so a target or average bitrate can only provide an estimate.
How to use the estimate in your workflow
- Check the expected duration of the final cut.
- Use the bitrate from your editor’s export settings, not the speed of your internet connection.
- Include audio bitrate if the file contains audio.
- Leave extra storage for the actual export, project files, and temporary files.
- When the file is ready, estimate the transfer with the video upload time calculator.
If your goal is a maximum file size, start with an appropriate export preset and test a short sample. A target-size workflow may require calculating the average bitrate backwards from the duration and size limit.
Frequently asked questions
How many MB is a one-minute video?
There is no single size for every one-minute video. At a combined bitrate of 8.192 Mbps, a one-minute clip is about 61.44 decimal MB. Lower or higher bitrates produce different estimates.
Why is my exported video larger than the calculator estimate?
The file may use a higher achieved bitrate than expected, include additional streams, or contain metadata and container overhead. Variable-bitrate output can differ from a target average.
Is Mbps the same as MB/s?
No. Mbps means megabits per second, while MB/s means megabytes per second. Eight bits make one byte, so 8 Mbps is roughly 1 MB/s before overhead.
Does a higher bitrate always improve video quality?
No. Codec, resolution, frame rate, scene complexity, and encoder settings all matter. Higher bitrate can reduce compression artifacts, but it also increases file size and may offer diminishing returns.
Need to plan the transfer as well?
Estimate upload time