PixelTools

Bitrate Calculator

Figure out what bitrate a file was encoded at, or what bitrate you need to hit a target file size.

File size (MB)

Duration (s)

Bitrate (Mbps)

13.333

Useful for figuring out what bitrate a video was encoded at, or what bitrate you'd need to hit a target file size.

What you entered

File size (MB): 500Duration (s): 300

1
Bitrate = (file size × 8) ÷ duration
(500 MB × 8) ÷ 300 s= 13.3333 Mbps

Result

Bitrate (Mbps): 13.333

A 500 MB file over 300s averages 13.333333333333334 Mbps.

Average bitrate from file size and duration

Bitrate is file size converted to bits, divided by running time. This is the average across the file; variable-bitrate encodes swing above and below it.

File size	Duration	Average bitrate
100 MB	60 s	13.33 Mbps
700 MB	1 hour	1.56 Mbps
1,400 MB	1 hour	3.11 Mbps
4,000 MB	2 hours	4.44 Mbps
25,000 MB	2 hours	27.78 Mbps

For reference, streaming services use roughly 3-5 Mbps for 1080p and 15-25 Mbps for 4K, so the last row is around Blu-ray quality.

Higher bitrate generally means better quality (up to a point)

More bits per second of video or audio generally means more detail retained, but returns diminish — beyond a certain bitrate, further increases produce file size growth with little visible or audible quality improvement.

Working backward to hit a target file size

This same formula rearranges to solve for target file size (bitrate × duration ÷ 8) — useful when you know a size constraint (like a platform's upload limit) and need to pick an encoding bitrate that fits.

Frequently asked questions

My 10-minute video is 1.5 GB — what bitrate was it encoded at?

About 20 Mbps. That's typical for 1080p high-quality video (YouTube recommends 8-12 Mbps for 1080p uploads). 4K video at similar quality runs 35-68 Mbps.

What bitrate do I need for a YouTube upload?

YouTube recommends 8 Mbps for 1080p30, 12 Mbps for 1080p60, and 35-45 Mbps for 4K. Higher bitrates give YouTube better source material to re-encode, but very high bitrates beyond these recommendations show diminishing returns.

How do I hit a specific file size limit?

Divide the target file size by the video duration. For example, to fit a 5-minute video under 100 MB: 100 MB = 800 Mb, divided by 300 seconds = about 2.67 Mbps maximum average bitrate.