File size and bitrate calculator
How big is a video or audio file for a given bitrate and length, and what bitrate fits a target size?
Extra bytes the file format adds around the streams. Leave blank to ignore it; enter your format’s figure if you know it.
What the numbers mean
A bitrate is the amount of data a stream uses each second. Multiply it by the length of the recording and you have the size of the stream; add the other streams and the wrapper the file format puts around them and you have the size of the file. This calculator does that in both directions: from the video and audio bitrate and the duration to the size, and from a target size to the video bitrate that still fits. Two more modes size uncompressed (PCM) audio and uncompressed video from their sample rate, bit depth and frame size, which is how capture drives and archives are planned. Sizes appear in decimal megabytes and in binary mebibytes, because the file manager on your computer may use either.
The formulas
File size in bytes = (video bitrate + audio bitrate) in bits per second × seconds ÷ 8 × (1 + overhead). The division by 8 is the step from bits to bytes. For a target size, the video bitrate is target size × 8 ÷ (1 + overhead) ÷ seconds − audio bitrate. Uncompressed audio is sample rate × bit depth × channels per second; uncompressed video is width × height × bits per pixel × frames per second, where bits per pixel is the number of samples per pixel (3 for RGB or 4:4:4, 2 for 4:2:2, 1.5 for 4:2:0) times the bit depth. A kilobit is 1,000 bits here, as in kbps on a streaming service.
Worked example: a 10-minute 1080p upload
YouTube’s recommended 1080p SDR bitrate for 24 to 30 frames per second is 8 Mbps, with 384 kbps for stereo audio. Over 600 seconds that is (8,000,000 + 384,000) × 600 ÷ 8 = 628,800,000 bytes, or 628.8 MB, which a computer using binary units reports as 599.7 MiB. If the container added 2% on top, the file would be 641.4 MB; the overhead box is empty by default because the right percentage depends on the format and we did not find a sourced figure to put there.
YouTube’s recommended upload settings (SDR)
| Resolution | 24, 25, 30 fps | 48, 50, 60 fps |
|---|---|---|
| 2160p (4K) | 35–45 Mbps | 53–68 Mbps |
| 1440p | 16 Mbps | 24 Mbps |
| 1080p | 8 Mbps | 12 Mbps |
| 720p | 5 Mbps | 7.5 Mbps |
| 480p | 2.5 Mbps | 4 Mbps |
| 360p | 1 Mbps | 1.5 Mbps |
From Google’s YouTube Help page “Recommended upload encoding settings,” read on October 27, 2026; the page shows no revision date, and an HDR table and an 8K row exist there too. Audio: 48 kHz, 384 kbps stereo, 128 kbps mono, 512 kbps 5.1. Use these as starting points for the bitrate box, not as a guarantee of quality.
Limits of this method
The formula uses one average bitrate. An encoder that varies the bitrate with the picture produces a file whose size is its measured average bitrate times the duration, so enter the average of your own encode rather than the peak. Container overhead is real but format-dependent; the calculator does not guess it. Uncompressed numbers are ceilings: a real video file is compressed far below them, and audio in AAC or Opus has whatever bitrate the encoder was told to use. Finally, a bitrate is not a download speed: to see how long a file of this size takes to move over a connection, use the download time calculator.
Common mistakes
Forgetting the factor of 8 and reading Mbps as MB/s, which makes every file eight times too large. Mixing units: 8,384 kbps is 8.384 Mbps, not 8.384 kbps. Comparing a size in MB with one in MiB, which differ by 4.9% at the megabyte scale and about 7.4% at the gigabyte scale. Ignoring the audio track in an audio-heavy file. Using the resolution to estimate size: a 1080p file can be any size, and the bitrate decides it. To work out the shape of the picture first, use the aspect ratio calculator, and for pixel density on a screen the PPI calculator.
How do I calculate video file size from the bitrate?
Add the video and audio bitrates, multiply by the duration in seconds and divide by 8 to turn bits into bytes: size = (video bitrate + audio bitrate) × seconds ÷ 8. A 10-minute clip at 8 Mbps video and 384 kbps audio is (8,000,000 + 384,000) × 600 ÷ 8 = 628,800,000 bytes, which is 628.8 MB or 599.7 MiB. One hour at the same rates is 3.77 GB. The audio is only 4.6% of the total, which is why video bitrate dominates file size.
How do I find the bitrate for a target file size?
Reverse the formula: total bitrate = size × 8 ÷ seconds, then subtract the audio bitrate. To fit a 90-minute film in 700 MB with 128 kbps audio, the total is 700,000,000 × 8 ÷ 5,400 = 1,037,037 bits per second, and the video gets 909.04 kbps. If you expect container overhead, divide the target size by (1 + overhead) first; the calculator’s overhead box does that. When the audio and overhead already use up the whole size, no video bitrate is possible, and the calculator says so.
How big is uncompressed audio?
Uncompressed (PCM) audio takes sample rate × bit depth × channels bits per second. CD audio is 44,100 samples per second at 16 bits in two channels (the Library of Congress gives the 44.1 kHz and 16 bits, the National Archives the stereo field): 44,100 × 16 × 2 = 1,411,200 bits per second, or 1,411.2 kbps. That is 10,584,000 bytes a minute (10.58 MB, 10.09 MiB) and 635 MB an hour. Compressed formats such as AAC or Opus are far smaller because their bitrates are set by the encoder, not by these three numbers.
How big is uncompressed video?
Width × height × bits per pixel × frames per second. A pixel needs 3 samples in RGB or 4:4:4, 2 on average in 4:2:2 and 1.5 in 4:2:0, each of the chosen bit depth. At 1920 × 1080, 8 bits, 30 frames per second, 4:4:4 comes to 1,492,992,000 bits per second, 1.493 Gbps, or 11.2 GB for one minute; 4:2:0 halves that to 746.496 Mbps and 5.6 GB a minute. An 8 Mbps upload is about 93 times smaller than the 4:2:0 figure, so these numbers are a ceiling, useful for sizing capture drives rather than finished files.
What is the difference between MB and MiB, and Mbps and MB/s?
NIST’s page on binary prefixes explains that kibi, mebi and gibi were approved by the IEC for powers of 1,024 (IEC 60027-2): 1 MiB is 2^20 = 1,048,576 bytes, while 1 MB is 1,000,000 bytes, so 628.8 MB is the same file as 599.7 MiB. Mbps is megabits per second and MB/s is megabytes per second, eight times larger: an 8.384 Mbps stream moves 1.048 MB every second. The calculator shows both unit systems for every size.
What bitrate does YouTube recommend for uploads?
YouTube’s help page “Recommended upload encoding settings” (read October 27, 2026) lists, for SDR video at 24, 25 or 30 frames per second, 8 Mbps at 1080p, 5 Mbps at 720p and 35 to 45 Mbps at 2160p, with higher figures for 48 to 60 frames per second; the full SDR table is above. For audio it recommends 48 kHz and 384 kbps for stereo, 128 kbps for mono and 512 kbps for 5.1. These are the platform’s recommendations for files you upload, not a measure of quality or of what a viewer receives; the page carries no revision date, so check it before relying on the numbers.
Sources: NIST, “Prefixes for binary multiples” (IEC 60027-2: kibi, mebi, gibi); Library of Congress, Sustainability of Digital Formats, “Linear Pulse Code Modulated Audio (LPCM)” (audio CDs use 44.1 kHz and 16-bit samples); U.S. National Archives, “CD-R Output [AUD-D1]” (44.1 kHz, 16 bit, stereo); YouTube Help, “Recommended upload encoding settings” (read October 27, 2026). Related: download time calculator, data storage converter, aspect ratio calculator, PPI calculator and RAID calculator for the storage the files end up on.