Set Your Limit
Enter the maximum file size your platform allows Discord, X/Twitter, email, or any custom cap.
100% Client-Side · No Video Uploaded
A video bitrate calculator works backward from your target file size limit to determine the maximum video and audio bitrates. Enter file size cap (Discord 25MB, email 10MB), video duration, resolution, and codec to get exact encoder settings for Premiere Pro or DaVinci Resolve.
Export Parameters
Export Settings
? Target Video Bitrate
Total Bitrate
Audio Allocation
Predicted File Size
Video : Audio Split
Bits Per Pixel
Codec Efficiency
Quality Assessment
Unwatchable
Low
Acceptable
Good
Excellent
Enter your parameters to see the quality forecast.
File Size Breakdown
Video
Audio
Overhead (~1%)
Export Commands
ffmpeg -i input.mp4 -c:v libx264 -b:v ____k -c:a aac -b:a 128k output.mp4Configure your export settings as shown above.Configure your Deliver page settings as shown above.handbrake-cli -i input.mp4 -o output.mp4 -e x264 -b ____ -B 128Resolution Comparison
Same file size limit at different resolutions
| Resolution | Video Bitrate | BPP | Quality |
|---|---|---|---|
| Enter parameters to see the comparison. | |||
How It Works
Add Duration
Specify how long your video is in minutes and seconds. Choose your codec and frame rate.
Get Bitrate
We calculate the exact bitrate to fit your file under the limit and assess the resulting quality.
Copy & Export
Get copy-paste FFmpeg commands, Premiere Pro settings, DaVinci Resolve config, and Handbrake CLI.
Video Editing Efficiency Gear
If you are frequently exporting videos and battling file size limits, your export render times are likely slowing you down. We strongly recommend editing on a high-speed NVMe SSD to eliminate timeline lag and drastically speed up your encoding. For dialing in complex export settings without clicking through endless menus, map your custom export presets to a macro editing console to streamline your workflow.
How to Calculate Video Bitrate from File Size
When you are trying to share a video on Discord (which has a strict 25MB limit for free users) or X/Twitter (512MB limit), you can't just guess your export settings. If you export at too high a bitrate, the file will be too large and the platform will reject it. If you export too low, the video will look like a pixelated mess. Video File Size = Total Bitrate × Duration. BitrateBoss reverses this equation. You input the strict file size limit and the exact duration of your video, and we calculate the maximum allowable video and audio bitrate. We even account for container overhead and provide copy-paste FFmpeg commands so you can compress your video to hit the limit perfectly, without losing unnecessary quality.
Frequently Asked Questions
How do you calculate video bitrate from a file size limit?
Bitrate = (Target File Size in bits - Audio Bitrate × Duration) / Duration. For a 25MB Discord limit with a 60-second video and 128kbps audio: (25 × 8,388,608 - 128,000 × 60) / 60 = 3,365 kbps video bitrate. This is the maximum video bitrate that will keep the file under the limit.
What bitrate is good enough for 1080p video?
YouTube recommends 8,000 kbps for 1080p at 30fps and 12,000 kbps at 60fps. Below 5,000 kbps, compression artifacts become visible in high-motion scenes. Below 2,500 kbps, quality degrades noticeably in all content. For screen recordings with little motion, 3,000-4,000 kbps at 1080p looks acceptable.
What is the difference between CBR and VBR encoding?
Constant Bit Rate (CBR) maintains the same bitrate throughout the video — predictable file sizes but wastes bits on static scenes. Variable Bit Rate (VBR) allocates more bits to complex scenes and fewer to simple ones — better quality per byte but less predictable file sizes. Use CBR for streaming and VBR for file uploads.