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About Video Bitrate Calculator Online

This tool calculates the bitrate required to encode a video to a target file size, or the file size resulting from a chosen bitrate. Enter resolution, frame rate, duration, and either target size or bitrate, and the calculator returns the missing value.

Bitrate is the trade-off between video quality and file size. Higher bitrate preserves detail but bloats the file; lower bitrate saves space but introduces compression artifacts. Most platforms have recommended bitrate ranges — YouTube suggests 8 Mbps for 1080p 30fps, 12 Mbps for 1080p 60fps, and 35–45 Mbps for 4K 30fps.

Use it when targeting a specific file size for upload (Discord caps at 25 MB, Twitter at 512 MB), preparing a video for a streaming platform, or planning storage for raw camera footage.

How to use this tool

How to estimate video file size from bitrate and duration

  1. Bitrate in kbps

    "Bitrate (kbps)" is the constant or average encoder bitrate in kilobits per second. Typical: 720p H.264 ~2500 kbps, 1080p ~5000 kbps, 4K HEVC ~20000 kbps.

  2. Duration in seconds

    "Duration (seconds)" is the clip length. Convert from minutes (×60) or HH:MM:SS manually — the tool only accepts seconds.

  3. Press Run

    Result returns sizeMB = (kbps × seconds) / 8 / 1024, rounded to 2 decimals. Math: kb/s × s ÷ 8 = kilobytes, then ÷ 1024 to MB.

  4. Real files include audio + container

    This estimate is video-track only. A 192 kbps stereo AAC adds about 1.4 MB per minute; MP4 container overhead is small (<1%). For exact targets, encode and check, then iterate bitrate.

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