Video Bitrate Calculator — Bitrate ⇄ File Size
Convert video bitrate and duration to file size, or a target file size to the required bitrate — with YouTube upload bitrate reference values.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Recommended bitrate — by codec & quality
Values are Mbps (video + audio). Tap one to load it into the calculator above.
H.265 / HEVC needs roughly half the bitrate of H.264 for the same quality, and AV1 a little less again; VP9 sits near HEVC. High-motion content (sports, live) needs much more than talking-head footage. All figures are rough starting points — modern encoders adapt to the actual scene.
Bitrate covers video + audio combined; bytes = bits × seconds ÷ 8 (1 MB = 10⁶ bytes). Real encoder output varies with content, so treat results as estimates.
About this tool
Work out video file sizes and bitrates in both directions. Enter a bitrate and duration to see how large a recording or stream will be, or enter a target file size to find the bitrate that fits — handy for uploads with size limits, estimating storage for security cameras, or planning a live stream. Reference values for popular platforms such as YouTube and Twitch are built in, so you can sanity-check your settings. All the math runs in your browser; no video or data is ever uploaded.
Frequently asked questions
How is video file size calculated from bitrate?
The core formula is simple: bitrate multiplied by duration, then divided by eight to convert bits into bytes. For example, a 10-minute video at 8 Mbps is 8 megabits × 600 seconds = 4,800 megabits, or 600 MB. Remember to add the audio track — typically 128–320 kbps — since most bitrate settings you see quoted are for video only. This tool performs the conversion and unit handling for you, entirely on your device.
What is the difference between CBR and VBR?
CBR (constant bitrate) keeps the data rate fixed throughout, so file size is perfectly predictable — that is why live streaming platforms usually require it. VBR (variable bitrate) lets the encoder spend more bits on complex, fast-moving scenes and fewer on static ones, giving better quality per megabyte for recorded files. For VBR, this calculator's result is an estimate based on the average bitrate; the actual file can land somewhat above or below it.
What bitrate should I use for YouTube or Twitch?
As a guide, YouTube recommends roughly 8 Mbps for 1080p uploads at 30 fps, 12 Mbps at 60 fps, and 35–45 Mbps for 4K, while Twitch caps live streams at 6–8 Mbps, with about 6 Mbps typical for 1080p60. Your upload bandwidth matters too: streaming at 6 Mbps needs comfortable headroom above that. The reference values are built into this tool, and since it runs entirely in your browser, you can experiment freely without sending anything anywhere.