How the video bitrate calculator works
Bitrate, duration and file size are tied together by one formula:
file size (bytes) = (video bitrate + audio bitrate) × duration in seconds ÷ 8
Pick what you want to calculate and enter the other two. The video file size calculator handles the three common jobs:
- File size: how big will a recording or export be?
- Bitrate: what bitrate fits a size limit, like an upload cap or a 4 GB card?
- Duration: how many minutes of footage fit in a given amount of storage?
Examples
- 1080p export: 8 Mbps video + 128 kbps audio for 10 minutes ≈ 610 MB. An hour at the same settings is about 3.66 GB.
- Fitting a size limit: to squeeze a 60 minute video into 2 GB with 128 kbps audio, the total bitrate is 2,000,000,000 × 8 ÷ 3,600 ≈ 4.44 Mbps, so set the video to about 4.3 Mbps.
- Storage planning: 4 GB at 5 Mbps video + 128 kbps audio holds about 1 hour 44 minutes.
Units: bits vs bytes, decimal vs binary
Bitrates are measured in bits per second (kbps, Mbps) and file sizes in bytes (MB, GB); one byte is 8 bits. This bitrate calculator treats MB and GB as decimal (1 GB = 1,000,000,000 bytes) and shows binary units (MiB, GiB, based on 1,024) separately, so the numbers match whichever app you check them in.
YouTube’s recommended upload bitrates
YouTube publishes recommended video bitrates for SDR uploads. They’re a useful reference for choosing export settings:
| Resolution | 24, 25, 30 fps | 48, 50, 60 fps |
|---|---|---|
| 2160p (4K) | 35–45 Mbps | 53–68 Mbps |
| 1440p (2K) | 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 |
For audio, YouTube recommends 128 kbps for mono, 384 kbps for stereo and 512 kbps for 5.1.
Source: YouTube Help, “YouTube recommended upload encoding settings” (checked November 2026).
Writing a script for your video? The words to minutes calculator tells you how long it will run.
Frequently asked questions
How do I calculate video file size from bitrate?
Add the video and audio bitrates, multiply by the duration in seconds, and divide by 8 to turn bits into bytes. For example, 8 Mbps video plus 128 kbps audio for 10 minutes is 8.128 million bits per second × 600 seconds ÷ 8 ≈ 610 MB.
What bitrate do I need to fit a video in a certain size?
Choose “Bitrate” above, enter the target file size and the video’s length. The calculator divides the size (in bits) by the duration and subtracts your audio bitrate to give the video bitrate to set in your encoder. Leave a small margin, because the container adds a little overhead.
What is the difference between MB and MiB?
MB (megabyte) is decimal: 1,000,000 bytes. MiB (mebibyte) is binary: 1,048,576 bytes. Drive makers and most video tools use decimal units, while Windows reports sizes in binary units but labels them MB and GB, which is why a “1 GB” file can show as about 0.93 GB in Windows.
What is the difference between Mbps and MB/s?
Mbps is megabits per second; MB/s is megabytes per second. There are 8 bits in a byte, so 8 Mbps equals 1 MB/s.
Why is my real file a little different from the estimate?
Most encoders use variable bitrate, so the actual average can drift from the target, and the file container adds a small amount of overhead. The calculation is exact for the bitrates you enter; real files land close to it.