VideoShrinkEstimate a one-minute video
At 2.5 Mbps video and 128 kbps audio, a 60-second video is about 19.71 MB (18.80 MiB).
Free planning tool
Video File Size Calculator
Estimate file size from duration and bitrate, or work backward from a target size to the bitrate your video can use.
No upload required
Calculate size or bitrate
Estimated file size19.71 MB18.8 MiB · 19,710,000 bytes
Estimate only. Variable bitrate, container overhead, metadata and encoder behavior can change the final file size.
Transparent calculation
The video file size formula
The result comes from the amount of data used each second. No video analysis or upload is involved.
File size in bytes
(video kbps + audio kbps) × duration in seconds × 1,000 ÷ 8To calculate a target bitrate, rearrange the same formula and subtract the audio bitrate from the total.
Plan for a 25 MB limit
For a 2-minute video with 96 kbps audio, the theoretical video bitrate is about 1.57 Mbps.
Why estimates differ
Bitrate is the main input, not the whole file
Real encoders may use more data for motion and detail and less data for simple scenes. Containers also add indexes, timestamps and metadata.
- Variable bitrate changes data use from scene to scene.
- Container overhead adds a small amount beyond audio and video tracks.
- Codec efficiency affects quality at a given bitrate, not the bitrate formula itself.
Clear answers
Video file size calculator FAQs
How do I calculate video file size?
Add the video and audio bitrates, multiply by the duration in seconds, then divide by eight to convert bits to bytes. The calculator applies that formula instantly.
Why is the exported video a different size?
The formula is an estimate. Variable bitrate, container overhead, metadata, encoder decisions and short bitrate spikes can make the finished file slightly larger or smaller.
What is the difference between MB and MiB?
One decimal megabyte (MB) is 1,000,000 bytes. One mebibyte (MiB) is 1,048,576 bytes. Upload limits usually use MB, while some operating systems and apps display binary units.
Does this calculator upload my video?
No. It only uses the numbers entered in the form. You do not need to select or upload a video file.
Ready to make the file smaller?
Use the calculated bitrate as a planning target, then compress the video locally in your browser.
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