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Video Size Calculator

Estimate a video file size from its bitrate and duration — or work out the bitrate you need to hit a target size. Free and instant.

Free · No sign-upNo sign-upNo credit card

Need to email a clip under 25 MB, or fit a video on a drive? File size comes down to bitrate × duration. This free video size calculator estimates the final size from your bitrate and length, or tells you the bitrate to hit a target size — no guesswork before you export.

Quality preset
Bitrate (Mbps)
Minutes
Seconds
75.0 MB

Estimated file size at 10 Mbps for 1m 0s

How it works

1

Enter your values

2

See the result update instantly

3

Use it to plan or resize your video

Frequently asked questions

How is video file size calculated?

Roughly: file size ≈ bitrate × duration. A higher bitrate or a longer video means a larger file. This tool does the conversion between megabits and megabytes for you.

What bitrate should I use?

For 1080p, 8–12 Mbps looks great; for 720p, 5–7.5 Mbps; for 4K, 35–45 Mbps. Lower it to shrink the file, raise it for more quality.

How do I make my video smaller?

Lower the bitrate or resolution, or shorten the clip. To compress without the math, use our free Video Compressor.

Is this tool free?

Yes — it is 100% free, runs in your browser, and needs no account.