Video File Size Calculator

About this calculator

This calculator estimates a video file's size as bitrate × duration, converting the result from bits to bytes (dividing by 8) and then to megabytes or gigabytes. Bitrate measures how much data is encoded per second of footage, and it varies enormously by resolution and codec: streaming platforms typically recommend around 8 Mbps for 1080p and 35–45 Mbps for 4K, while variable bitrate (VBR) encoding — common in modern codecs like H.264 and H.265 — allocates more data to complex, high-motion scenes and less to static ones, so actual file size can differ from a constant-bitrate estimate.

Video editors and YouTubers use this to estimate upload sizes and plan render/export settings, videographers use it to figure out how much footage fits on an SD card or drive before a shoot, and streaming and broadcast engineers use similar math to set encoding presets that balance quality against bandwidth. Enter a bitrate and duration to estimate the resulting file size.