Video Bitrate Calculator

About the Video Bitrate Calculator

A video file's size depends almost entirely on two things: its bitrate, the amount of data used for each second of footage, and its length. Whether you are exporting a project from an editor, setting up a live stream, archiving recordings or trying to squeeze a video under an upload limit, knowing how bitrate and size relate saves guesswork and repeated exports.

This video bitrate calculator works in both directions. In file size mode it works out how large a video will be from its video bitrate, audio bitrate and length. In bitrate mode it finds the video bitrate needed to hit a target file size. It also gives the total bitrate, the size per minute and per hour, and a comparison with typical bitrates for common resolutions.

How to Use the Video Bitrate Calculator

Choose File size from bitrate or Bitrate for a file size.

For a file size, enter the video bitrate in Mbps — your editor or encoder shows this in its export settings.

For a bitrate, enter the target file size in MB, such as an upload limit.

Enter the audio bitrate in kbps. 128 kbps is common for speech, 192 kbps for general video and 320 kbps for high-quality music.

Enter the length of the video in hours and minutes.

How Video Size Is Worked Out

  total bitrate   =  video Mbps + audio kbps ÷ 1,000
  file size (MB)  =  total bitrate × seconds ÷ 8
  video bitrate   =  target MB × 8 ÷ seconds − audio kbps ÷ 1,000
  MB per minute   =  total bitrate × 60 ÷ 8

Dividing by 8 turns megabits into megabytes, because a byte is 8 bits.

Step-by-Step Example: File Size

One hour of 1080p video at 8 Mbps with 192 kbps audio.

  Total rate:  8 + 0.192 = 8.192 Mbps
  Megabits:    8.192 × 3,600 s = 29,491 megabits
  Size:        29,491 ÷ 8 = 3,686 MB, about 3.69 GB
  Per minute:  8.192 × 60 ÷ 8 = 61.4 MB

So an hour of video at this quality takes about 3.69 GB, about 61.4 MB for each minute.

Step-by-Step Example: Bitrate for a Target Size

A 45-minute video that must fit in 700 MB, with 128 kbps audio.

  Megabits:     700 MB × 8 = 5,600 megabits
  Total rate:   5,600 ÷ 2,700 s = 2.074 Mbps
  Video:        2.074 − 0.128 = 1.946 Mbps

Set the video to about 1.95 Mbps. That is well below the usual rate for 1080p, so for the best result at this size, export at 720p or use a more efficient codec.

Typical Bitrates

For uploading standard dynamic range video at 24 to 30 frames a second, common recommendations are roughly:

  720p     5 Mbps
  1080p    8 Mbps
  1440p   16 Mbps
  4K      35 – 45 Mbps

Video at 50 or 60 frames a second, and HDR video, need roughly half as much again. Streaming services deliver at lower rates than these, because they re-encode uploads carefully and adapt quality to each viewer's connection. Cameras record at much higher rates, often 50 to 150 Mbps or more, to keep maximum detail for editing.

Codecs and Quality

The codec — the method used to compress the video — changes how much quality each bit buys. H.264 (AVC) is the most widely compatible. H.265 (HEVC) typically reaches similar quality at around half the bitrate, and AV1 does slightly better again, at the cost of slower encoding and less support on older devices. When a file must be small, a newer codec is often a better choice than a lower bitrate.

Content matters too. A talking head against a plain wall compresses easily; sport, confetti, water and film grain need far more bits to look clean. If your footage is busy, use the upper end of the typical range.

Constant and Variable Bitrate

A constant bitrate (CBR) spends the same number of bits every second, which suits live streaming because the connection sees a steady load. A variable bitrate (VBR) spends more on complex scenes and less on simple ones, giving better quality for the same average size, which suits files. With VBR the final size is close to the calculation but rarely exact; a two-pass encode gets nearest to a target.

Planning Storage and Uploads

Knowing the size per minute makes storage planning simple. At 61.4 MB a minute, a full day of recording at 8 Mbps with 192 kbps audio fills about 88 GB, so a 1 TB drive holds a little over eleven days of footage. Security cameras often record at 2 to 4 Mbps to stretch storage further, trading detail for time.

Uploads work the same way in reverse. A 3.69 GB file on a connection that uploads at 20 Mbps takes about 25 minutes at full speed, and longer in practice. If an upload must finish quickly, a lower bitrate or a more efficient codec is often the practical answer, since the file size falls in direct proportion to the bitrate.

Understanding Your Result

The headline is the file size in file size mode, or the video bitrate in bitrate mode.

The total bitrate combines video and audio.

The size per minute and per hour help you plan storage and upload limits.

The length confirms the duration used.

The typical bitrates line shows which resolution your bitrate usually suits.

When Should You Use This Calculator?

Use it before exporting, to choose settings that fit an upload or email limit.

Use it to estimate storage for recordings, security footage or an archive.

Use it to set a streaming bitrate that your upload speed can sustain.

Use it to compare how much space different quality settings will take.

Common Mistakes

Forgetting the audio. Audio adds to every second; at low video bitrates it is a noticeable share.

Mixing bits and bytes. Bitrates are in megabits; file sizes are in megabytes. Divide by 8.

Choosing too low a bitrate for the resolution. Drop the resolution instead of starving a high one.

Expecting an exact size with VBR. Variable bitrate lands close to the target, not exactly on it.

Streaming at your full upload speed. Leave about a quarter of the upload free so the stream does not stall.