FFmpeg Cookbook
JA

Bitrate Calculator

Estimate video and audio bitrates from resolution, frame rate and quality, and compare them with reference values for YouTube, Twitch and others.

Video Bitrate
—
kbps
Audio Bitrate
—
kbps
Total Bitrate
—
kbps

Platform Reference Values

Platform Resolution / FPS Video (kbps) Audio (kbps) Total (kbps)

Values from each service's own page (checked September 2026). YouTube: recommended upload bitrates for standard (SDR) video and stereo audio; mono audio is 128 kbps and 5.1 is 512 kbps. Twitch: broadcasting guidelines, CBR video; 96 kbps audio is recommended and 160 kbps is the maximum. Facebook: recommended Live settings, 1080p at 30 fps and 3,000–6,000 kbps. The services may change these values.

Popular uses
Back-calculate from target sizePlan streaming bitrateBuild settings for social or email
Next tools
File Size Estimator Video Compressor Codec Compatibility Matrix

How to use

  1. Pick resolution / FPSResolution from 360p to 4K, frame rate from 24 to 60 fps.
  2. Pick qualityHigh, Medium or Low.
  3. Read resultVideo, audio and total bitrate appear. The table below shows each service’s recommendation for the resolution you picked.

Recommended settings

1080p 30 fps upload to YouTube
Video 8 Mbps + audio 384 kbps (stereo)
YouTube’s published recommendation. Mono audio is 128 kbps.
1080p 60 fps stream on Twitch
Video 6,000 kbps (CBR) + audio 96–160 kbps (AAC)
Twitch’s broadcasting guidelines: 96 kbps audio recommended, 160 kbps maximum.
Smaller 720p file
720p · 30 fps · Low (video 1,500 kbps + audio 128 kbps)
Half the video bitrate of Medium (3,000 kbps).

When it goes wrong

The file size does not match the calculation

Cause: Only the video bitrate was counted. Also, -b:v is an average target, so the real rate varies a little.

Fix: Add video and audio together and leave some margin.

Questions

Bitrate ↔ size?

Size in MB ≈ total bitrate (kbps) × seconds ÷ 8 ÷ 1000. For example, 5,000 kbps for 60 seconds is about 37.5 MB.

CBR or VBR?

Live streams normally use CBR (constant bitrate), and Twitch recommends it. For saved files, CRF or VBR usually gives a smaller file at the same quality.

More detail (settings, limits, FFmpeg commands)

What each setting means

Resolution / FPS
Higher resolution gives a higher value. 60 fps gets a higher value than 30 fps.
Quality Preset
Moves the value up or down at the same resolution. Audio is 320 kbps (High), 192 kbps (Medium) or 128 kbps (Low).

Browsers and limits

  • The values are estimates. The right bitrate depends on the content.

The same job with the FFmpeg command line

Encode at a set bitrate (average 5 Mbps, peak 5.5 Mbps)
ffmpeg -i input.mp4 -c:v libx264 -b:v 5000k -maxrate 5500k -bufsize 10000k -c:a aac -b:a 128k output.mp4
-b:v sets the average and -maxrate the peak. The rate still varies from scene to scene, so this is not CBR.

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