Video File Size Calculator by Format

Understanding video file sizes is essential for anyone working with digital video — from independent filmmakers and content creators to IT professionals managing storage infrastructure. A video file's size is determined by how many bits of data are required to represent each second of playback, a figure known as the bitrate. Multiply the bitrate by the duration and you get the file size; the challenge is that bitrate itself depends on resolution, frame rate, color depth, and the efficiency of the compression algorithm used by each container format. This calculator uses the formula: File Size (bytes) = (Bitrate × Duration in seconds) ÷ 8, where Bitrate (bps) = Width × Height × Frames per Second × Bit Depth × Compression Factor. The compression factor varies significantly by format. MP4 with H.264 encoding — the most common web format — achieves compression factors around 0.005, meaning it discards roughly 99.5% of the raw pixel data while maintaining acceptable perceptual quality. MOV with Apple ProRes keeps much more data (factor ~0.05), producing larger but color-graded-friendly files preferred in post-production. AVI in its uncompressed form retains nearly all raw data (factor ~0.9), generating enormous files used only in specialized archival or broadcast contexts. MKV with H.265 (HEVC) is the most efficient modern codec, achieving the same visual quality as H.264 at roughly half the file size. WebM with VP9 sits between H.264 and H.265 in efficiency. Bit depth also plays an important role. Standard 8-bit video encodes 256 levels of luminance and color per channel, which is adequate for most consumer content. Ten-bit video captures 1,024 levels, preserving fine gradations in highlights and shadows that benefit color grading workflows. Twelve-bit video offers 4,096 levels and is used in RAW cinema camera formats where maximum flexibility in post-production is required. Frame rate determines how many individual images are captured per second. Standard cinematic content uses 24 fps; broadcast television typically uses 25 or 30 fps; slow-motion and gaming content often runs at 60 fps or higher. Every increase in frame rate proportionally increases the bitrate and therefore the file size, all else being equal. Audio contributes a small but non-trivial fraction of total file size. A 128 kbps AAC stereo audio track adds about 60 MB per hour — negligible for a long film but significant for large batches of short clips. Higher audio bitrates (256–320 kbps) are used for music videos, concerts, and audiophile content. The examples built into this calculator cover the most common production scenarios: a standard 1080p YouTube upload, a 4K cinematic project, a 720p streaming-optimized file, and a high-frame-rate gaming recording. Use these as benchmarks to calibrate your expectations, then adjust the parameters to match your specific camera, editing software, and delivery platform requirements.