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Video file size and bitrate calculator

Bitrate and length in, file size out — or a target size in, and the bitrate that hits it.

Bitrate to file size

610 MB

600 MB of video plus 9.60 MB of audio, over 10m 0s.

File size to bitrate

6.54 Mbps

The video bitrate that fits 500 MB in 10m 0s with 128 kbps of audio alongside it.

Resolution24–30 fps48–60 fpsUse
2160p (4K)35 Mbps53 Mbps
1440p (2K)16 Mbps24 Mbps
1080p8 Mbps12 Mbps
720p5 Mbps7.5 Mbps
480p2.5 Mbps4 Mbps

YouTube's recommended SDR upload bitrates. Uploading above them does not improve what viewers see — YouTube re-encodes everything — but uploading well below gives the re-encoder less to work with. For a Twitch stream the practical ceiling is 6 Mbps.

What this does

File size in megabytes is bitrate in megabits per second multiplied by the length in seconds and divided by eight, plus the audio track on top. That is the whole calculation, and this does it in both directions: give it a bitrate and a duration for the resulting size, or give it a size cap and a duration for the bitrate you have to encode at to stay under it. It also carries the bitrates that are actually recommended for upload — YouTube's own figures for 1080p, 1440p and 4K at both standard and high frame rates, and Twitch's ceiling for a live stream — so you can see whether the number you need is one that will still look acceptable.

How to calculate video file size

  1. 01

    Enter the length

    Minutes and seconds, or a duration in seconds. This is the term everything else multiplies by, so it matters most.

  2. 02

    Give it a bitrate or a target size

    Either one solves for the other. The audio bitrate is added separately because at 128 or 192 kbps it is a rounding error on a video file and the whole of a long podcast export.

  3. 03

    Compare against the recommendations

    The table shows what YouTube asks for at each resolution and frame rate. If hitting your size cap means encoding well under that, the fix is usually a shorter video rather than a worse one.

Questions

What bitrate should I upload to YouTube at?

YouTube's recommendations for SDR are 8 Mbps for 1080p at 24–30fps and 12 Mbps at 48–60fps, 16 and 24 Mbps for 1440p, and 35 and 53 Mbps for 4K. Uploading above these does not improve what viewers see — YouTube re-encodes everything — but uploading well below them gives the re-encoder less to work with.

How big is a 10-minute 1080p video?

At YouTube's recommended 8 Mbps, about 600MB of video plus roughly 9MB of audio at 128 kbps. Halve the bitrate and you halve the file. The length is linear, so 20 minutes at the same bitrate is exactly twice as large.

Why is my exported file bigger than this says?

Almost always variable bitrate. A VBR encode spends more than the target on complex shots and less on simple ones, and the average can land above your setting on high-motion footage. Constant bitrate matches this calculation closely; VBR is an estimate.

What bitrate can I stream to Twitch at?

6000 kbps is the practical ceiling for video, and going above it risks buffering for viewers rather than better quality. 6000 at 1080p60 is Twitch's upper bound for most channels; 4500 at 936p60 is the setting that survives a less reliable connection.

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