What Is a Video Bitrate Calculator?
This calculator works backward from a target file size to find the bitrate you should encode at. Give it a file size limit, the clip's duration, and the audio bitrate you plan to use, and it returns the video bitrate to set in your encoder (HandBrake, FFmpeg, Premiere, etc.) so the finished file lands at your target size.
It's the everyday math behind fitting a video onto a disc, under an upload size cap, or within a fixed streaming data budget.
How to Read Your Results
Recommended Video Bitrate
The bitrate to set for the video stream alone in your encoder, after audio's share has already been subtracted from the total.
Total Bitrate (Video + Audio)
The combined bitrate needed to hit your target file size over the given duration — video and audio streams together.
Audio Bitrate
The value you entered, shown for reference alongside the split.
Duration Used
Your entered duration, converted to minutes and seconds, confirming what was used in the calculation.
Real-World Example
You need a 10-minute video to fit in a 500 MB upload limit, encoding audio at 128 kbps.
| Metric | Value |
|---|---|
| Target file size | 500 MB |
| Duration | 10m 0s |
| Total bitrate needed | ≈6,990 kbps |
| Audio bitrate | 128 kbps |
| Recommended video bitrate | ≈6,862 kbps |
Setting the encoder to roughly 6,862 kbps for video plus 128 kbps for audio should produce a file close to the 500 MB target, though actual results vary slightly with the codec and encoding mode used.
Tips for Hitting a File Size Target
- Use two-pass encoding when your encoder supports it — it hits target file sizes far more accurately than single-pass, constant-bitrate encoding.
- Leave a small margin (2–5%) below your hard size limit, since container overhead adds a little extra to the final file.
- Higher resolution or frame rate footage needs a higher bitrate to maintain the same visual quality — this calculator only sets the bitrate for a fixed size, not quality.
- Very low bitrates for the resolution will show visible compression artifacts regardless of the math working out.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team