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Video Bitrate Calculator

Find the bitrate that fits a target file size.

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Overhead depends on your container and muxer. Leave this at 0 for the raw payload size, or enter a value you have measured.

Video bitrate

13.205 Mbps
Total bitrate
13.333 Mbps
Audio share
1.0%

How this is calculated

The target size is converted to bytes, the container overhead is removed to leave the payload, and the payload is turned into bits and divided by the duration. Subtracting the audio bitrate from that total leaves the video bitrate to enter in your encoder.

targetBytes     = target size converted to bytes
payloadBytes    = targetBytes / (1 + overheadFraction)
payloadBits     = payloadBytes × 8
totalBitrateBps = payloadBits / durationSeconds
videoBitrateBps = totalBitrateBps − (includeAudio ? audioBitrateBps : 0)

Units

Bitrate is held in bits per second, capacity in bytes and duration in seconds. One byte is eight bits everywhere. Storage is decimal by default, so 1 GB is 1,000,000,000 bytes; binary units are opt-in and are always named GiB rather than GB.

Assumptions

  • The bitrate produced is an average target, not a guarantee about any single frame.
  • Container overhead is 0% unless you set it, because the real figure depends on your container and muxer and no measurement is published here.
  • No codec behaviour is modelled. The calculator does not know whether that bitrate looks good at your resolution, and it recommends none.

Read how every number on this site is derived.

Worked example

A 1 GB budget for a 10-minute export with a 128 Kbps audio track and no overhead:

targetBytes     = 1 GB                        = 1,000,000,000 bytes
payloadBytes    = 1,000,000,000 ÷ (1 + 0)     = 1,000,000,000 bytes
payloadBits     = 1,000,000,000 × 8           = 8,000,000,000 bits
totalBitrateBps = 8,000,000,000 ÷ 600         = 13,333,333.33… bps
videoBitrateBps = 13,333,333.33… − 128,000    = 13,205,333.33… bps
display (Mbps)                                = 13.205 Mbps

This is test vector V2 in the calculator requirements. Megabits are shown to three decimal places precisely so that a repeating value like this one stays checkable by hand.

Frequently asked questions

Why does container overhead divide here instead of multiplying?

Because the direction of the question is reversed. When you estimate a size, overhead is added to the payload. When you start from a size budget, the stored file already includes the overhead, so the payload available for picture and sound is the target divided by one plus the overhead fraction.

What happens if the audio alone fills my target?

The calculator says so rather than returning a negative or clamped number. Increase the target size, shorten the duration, or lower the audio bitrate. A negative video bitrate is not a result, so it is never shown as one.

Will an encoder hit this bitrate exactly?

A constant-bitrate encode comes close. A variable-bitrate encode targets an average, so the finished file usually lands within a few percent either way. If you must stay under a hard limit, aim a little below the figure shown and check the result before delivery.

Should I subtract the audio track?

Leave Include audio on whenever the export carries sound. The calculator subtracts the audio bitrate from the total so the figure shown is the video bitrate to enter in your encoder, not the combined stream rate. The combined rate is listed underneath as Total bitrate.

Can I take this bitrate to the other calculators?

Yes. The two links under the result carry the computed video bitrate into the file size and recording time calculators as a query parameter, so you do not have to retype it or convert it.