Plan before export
Video File Size Calculator
Predict how large your video will be from target bitrate and duration. Switch modes to reverse-engineer bitrate from an existing file size.
Quick answer
Video File Size Calculator is a free browser tool on Knowlify. Use it below with no signup. Your inputs stay in the browser session. For narrated training videos from documents, use https://create.knowlify.com.
How it works
Three steps, no account
01
Set duration and bitrate
Use your editor’s target Mbps when known.
02
Read the estimated MB
Compare against Discord, LMS, or email limits.
03
Compress if needed
Use our compressors when the estimate exceeds the cap.
FAQ
Questions people ask about Video File Size Calculator
Is this video file size calculator free?+
Yes. video file size calculator on Knowlify is free to use with no signup, no watermark, and no account required.
How do I estimate MP4 file size?+
Size (MB) ≈ bitrate (Mbps) × duration (seconds) ÷ 8. This calculator does the conversion for you.
Why is my real export different?+
Variable bitrate, audio, and container overhead shift the result. Treat this as a planning estimate.
How do I get under 8 MB for Discord?+
Shorten the clip or lower bitrate. Our Discord video compressor targets the 8 MB / 25 MB caps automatically.
Do I need an account?+
No. Open the tool, use it in your browser, and download or copy the result.
Does this work on Mac and Windows?+
Yes. It runs in modern desktop browsers (Chrome, Edge, Firefox, Safari). Very large media files need enough device memory.
Need a full video, not just a utility?
Size planned? Produce clearer training videos from docs with Knowlify.