Bitrate Calculator
Turn bitrate and duration into file size, or work backwards. Then find the right streaming bitrate for your resolution and upload speed.
Bitrate ⇄ file size ⇄ duration
Exact mathsPick what you want to find, fill in the other two, and the answer updates as you type.
File size
2.7GB
6,000 kbps for 1 h
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6,000,000 bit/s × 3,600 s ÷ 8 = 2,700,000,000 bytes
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Bitrate Converter
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File size per hour at common bitrates
Total bitrate, including audio. Decimal and binary units side by side.
| Bitrate | Per minute | Per hour | Per hour (binary) |
|---|---|---|---|
| 500 kbps | 3.75 MB | 0.225 GB | 0.21 GiB |
| 1,000 kbps | 7.5 MB | 0.45 GB | 0.419 GiB |
| 2,500 kbps | 18.8 MB | 1.13 GB | 1.05 GiB |
| 4,500 kbps | 33.8 MB | 2.03 GB | 1.89 GiB |
| 6,000 kbps | 45 MB | 2.7 GB | 2.51 GiB |
| 8,000 kbps | 60 MB | 3.6 GB | 3.35 GiB |
| 12 Mbps | 90 MB | 5.4 GB | 5.03 GiB |
| 20 Mbps | 150 MB | 9 GB | 8.38 GiB |
| 50 Mbps | 375 MB | 22.5 GB | 21 GiB |
| 100 Mbps | 750 MB | 45 GB | 41.9 GiB |
What bitrate means
Bitrate is how much data a video or audio stream uses per second. It ties three numbers together, so knowing any two gives you the third:
file size (bytes) = bitrate (bits per second) × duration (seconds) ÷ 8
- Recording or exporting? Bitrate × length tells you how much storage the file needs.
- Hitting an upload limit? Size ÷ length gives the bitrate that fits. The target file size calculator also subtracts audio and writes the ffmpeg command.
- Going live? Your bitrate has to fit inside your upload speed with room to spare. See the streaming bitrate calculator and the upload speed calculator.
Bitrates use decimal prefixes: 1 kbps is 1,000 bits per second and 1 Mbps is 1,000 kbps. File sizes are trickier, because Windows counts in binary units (1 “GB” = 1,073,741,824 bytes) while drive makers and macOS count in decimal. Use the Size units switch to match whichever you’re comparing against.
Frequently asked questions
How do I calculate file size from bitrate?
Multiply the bitrate in bits per second by the duration in seconds, then divide by 8 to get bytes. For example, 6,000 kbps for one hour is 6,000,000 × 3,600 ÷ 8 = 2,700,000,000 bytes, or 2.7 GB.
What is the difference between kbps and KB/s?
kbps is kilobits per second; KB/s is kilobytes per second. A byte is 8 bits, so 8,000 kbps is 1,000 KB/s (1 MB/s). Bitrates and internet speeds use bits; file sizes and download progress bars usually use bytes.
Why does Windows show my file as smaller than this calculator?
Windows Explorer uses binary units but labels them MB and GB: its "1 GB" is 1,073,741,824 bytes (a GiB). Drive makers, macOS and most websites use decimal units, where 1 GB is 1,000,000,000 bytes. Switch "Size units" to Binary to match Windows.
Should the bitrate include audio?
Yes. File size depends on the total bitrate of every stream in the file, so add the audio bitrate to the video bitrate. A 5,000 kbps video with 160 kbps audio is 5,160 kbps in total.
Why is my real file a little bigger or smaller?
Containers such as MP4 and MKV add a small amount of overhead (usually under 1–2%), and variable-bitrate encodes rarely hit their average exactly. Constant-bitrate encodes and streams land closest to the calculated size.