Tech
Video Bitrate Calculator
Solve any side of the video file size, bitrate, and duration triangle. Returns total and video-only kbps, MB output, HH:MM:SS duration, and a 1080p / 4K / 8K quality tier.
Video bitrate calculator
The encoded file size, in decimal MB (1 MB = 1,000,000 bytes).
Length of the video in seconds. 600 s = 10 minutes.
Audio track bitrate. 128 kbps is a typical AAC default.
Optional. Enables the bits-per-pixel quality classification.
Optional. 1920 x 1080 = Full HD, 3840 x 2160 = 4K UHD.
Required video bitrate
1,237.33 kbps
Total stream 1,365.33 kbps including 128 kbps audio.
- Total bitrate
- 1,365.33 kbps
- Video bitrate
- 1,237.33 kbps
- Audio bitrate
- 128 kbps
- Duration
- 00:10:00
- File size
- 100 MB
- Quality tier
- low
- Bitrate per megapixel
- 658.44 kbps/MP
Frequently Asked Questions about the Video Bitrate Calculator
What bitrate should I use for a YouTube upload?
YouTube's published recommendations land near 8 Mbps for 1080p at 30 fps, 12 Mbps for 1080p at 60 fps, 35 to 45 Mbps for 4K at 30 fps, and 50 to 68 Mbps for 4K at 60 fps for SDR content (HDR adds about 20 percent). Those are the target video bitrates only. Add 128 to 384 kbps for AAC audio to get the file's total stream rate, which is what the calculator uses to derive size or duration.
What is the difference between CBR and VBR?
Constant bitrate (CBR) holds the bitrate flat for every second of video, which makes file size and bandwidth perfectly predictable and is the default for live streaming and broadcast pipelines. Variable bitrate (VBR) lets the encoder spend more bits on motion-heavy or detailed scenes and fewer on static shots, so it produces a smaller file or higher quality at the same target. This calculator works on the average (effectively the CBR figure), so for a 2-pass VBR encode at the same average bitrate you will see the same file size with better perceived quality.
Why is the audio bitrate so much lower than the video bitrate?
Sound carries far less information per second than full-motion video, so modern codecs (AAC, Opus, MP3) produce near-transparent stereo at 128 to 320 kbps. That is about one to two percent of a typical 1080p video stream and rarely affects the file size meaningfully. The calculator defaults to 128 kbps but you can lower it for podcast-style speech (96 kbps mono is plenty) or raise it to 320 kbps for music-heavy content.
How much smaller is H.265 (HEVC) than H.264 for the same quality?
HEVC needs roughly half the bitrate of H.264 to reach the same visual quality. A 4K stream that calls for about 45 Mbps in H.264 looks comparable at 20 to 25 Mbps in H.265, and AV1 saves another 20 to 30 percent on top of HEVC. To use this calculator with HEVC or AV1, plug in your codec's target bitrate, not the H.264 number, and the resulting file size will track the smaller encode.
What is the formula linking file size, bitrate, and duration?
File size in MB = (total bitrate in kbps x duration in seconds) / 8192. The 8192 factor mixes the two conventions video tools use side by side: kbps is decimal kilobits (1 kbps = 1,000 bits per second), and MB here is the binary mebibyte (1 MB = 1,024 KB = 8,388,608 bits) that file systems report. The math collapses to (kbps x seconds) / (8 x 1024). Rearranging gives the other two solve modes: total bitrate = (size in MB x 8192) / seconds, and duration in seconds = (size in MB x 8192) / total bitrate.