Video File Size Calculator

How it is calculated

Enter the total bitrate in megabits per second (Mbps) and the length in minutes. The tool computes MB = bitrate × minutes × 60 ÷ 8: bitrate × minutes × 60 gives the total megabits, and dividing by 8 converts bits to bytes. Gigabytes are MB ÷ 1000, so the units are decimal (1 GB = 1,000 MB), not the 1,024 convention used by some operating systems. The bitrate should be the total of video and audio, since the tool does not add an audio track on its own. Both numbers must be above zero. Container overhead and variable bitrate are not modelled.

Common mistakes

• Entering the bitrate in kbps. A 5,000 kbps stream is 5 Mbps; typing 5000 here would give a size 1,000 times too large.
• Entering the duration in hours or seconds. The unit is minutes, so a 90-minute film is 90, not 1.5.
• Confusing megabits and megabytes. Bitrates are in bits (Mbps with a small b); the size comes out in bytes after the division by 8, which is why 8 Mbps does not mean 8 MB per second.
• Entering only the video bitrate when the file also has audio. Add the audio bitrate (for example 0.128 for 128 kbps) to get the real total.
• Expecting an exact size for variable-bitrate files. The result is for a constant bitrate; a VBR file will land above or below the estimate, so leave some headroom.