Video File Size Calculator

How it is calculated

The tool assumes a constant bitrate. Size in megabytes is MB = bitrate × duration × 60 ÷ 8, where bitrate is in megabits per second (Mbps) and duration is in minutes. Multiplying by 60 converts minutes to seconds, giving total megabits; dividing by 8 turns bits into bytes. Gigabytes are then GB = MB ÷ 1024, so the MB figure uses the 1,000-based megabit while the GB figure divides by 1,024; the two are not perfectly consistent, which matters only for large files. Both inputs must be above zero. The estimate covers the video stream alone as you describe it; audio tracks, subtitles and container overhead are not added, and variable-bitrate encodes will land above or below the result.

Common mistakes

• Entering the duration in seconds or hours. The field is minutes, so a two-hour film must be typed as 120; typing 2 shows a file that is 60 times too small.
• Mixing up megabits and megabytes. An 8 Mbps stream moves 1 megabyte per second; entering 8 as if it were MB/s overstates the size by 8 times.
• Entering the bitrate in kbps. A 5,000 kbps file is 5 Mbps; typing 5000 gives a result 1,000 times too large.
• Forgetting audio. A typical audio track adds its own bitrate, so for a precise total, add the audio bitrate to the video bitrate before using this tool.
• Assuming a variable-bitrate export will match. VBR files vary with scene complexity, so treat the answer as an average-case estimate.