How big will my video be? File size by codec

File size is bitrate multiplied by time. A 10 Mbps video collects 10 megabits every second, so 600 seconds of it is 6,000 megabits, and dividing by 8 turns that into 750 megabytes.

The full formula is (video bitrate + audio bitrate) × 1000 × seconds ÷ 8 = bytes, with the bitrates in kbps. Our worked example, 10 minutes at 10 Mbps plus one 128 kbps audio track, gives 10128 × 1000 × 600 ÷ 8 = 759,600,000 bytes, or 759.6 MB. The bitrate calculator opens with exactly that example filled in.

The table below is the same guidance the bitrate calculator's suggested-bitrate picker gives, from one rough rule: H.264 needs about 0.10 bits per pixel per frame, H.265 about 40 percent fewer bits for the same look, and 4K gets a small efficiency discount because modern encoders spread bits across far more pixels. Treat every number as a starting point. A steady interview can hold up at less; fast motion, grain, and confetti need more.

Audio adds its own bitrate, not a percentage. One 128 kbps stereo track adds 0.128 Mbps on top of the video, and a second track doubles that. Audio is small next to video, but it is not zero, and it is why the calculator asks for a track count.

Frame rate scales almost linearly. The table shows about 5.0 Mbps for 1080p H.264 at 24 fps and about 12.4 Mbps at 60. Same resolution, same codec, roughly two and a half times the data.

HDR pushes the target up. Highlights and gradients carry more information, so an HDR encode needs more headroom than the SDR version of the same scene. How much depends on the grade and the delivery spec, so treat the SDR number as a floor and add margin instead of trusting a fixed percentage.

Content decides how far a bitrate stretches. A still interview can look right at half the table's number, while fast motion and film grain eat bits quickly. If the export matters, encode a short representative clip at the target and check it before committing to the full render.

Once the math gives you a target, the Video Compressor re-encodes toward it. Set the target size, check the estimate it shows before the job runs, and watch a sample of the result before you rely on it.

Real encoders land near a target, not on it. Variable bitrate spends more on complex scenes and less on easy ones. Container overhead adds roughly 1 to 5%, so leave about 5% headroom for exact target sizes. When a hard cap is involved, check the size of the downloaded file before you upload it.

Changing codec or container instead of size? The Video Converter handles that, and it passes the streams through untouched when they already fit the target format.

If a finished file still bounces from an uploader, size is rarely the cause. The guide to why a video will not upload walks through the rest.