Video file size calculator
Enter the video bitrate in Mbps, the audio bitrate in kbps and how long the recording runs. See how much space the file takes and how much each minute adds.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the video bitrate in Mbps, as cameras, streaming software and encoders state it.
- Enter the audio bitrate in kbps; set 0 for silent footage.
- Enter the running time.
- Read the size in GB, with MB and GiB below it, and the size of each minute.
size in bytes = (video bitrate + audio bitrate) in bit/s × seconds ÷ 8
The calculator uses decimal units for MB and GB (1 MB = 1,000,000 bytes) and binary units for GiB (1 GiB = 2³⁰ = 1,073,741,824 bytes).
Worked example
8 Mbps of video with 192 kbps audio for 10 minutes:
- total bitrate 8,000,000 + 192,000 = 8,192,000 bit/s = 8.192 Mbps;
- 8,192,000 × 600 s = 4,915,200,000 bits ÷ 8 = 614,400,000 bytes;
- 614.4 MB, that is 0.61 GB or 0.57 GiB; one minute takes 61.4 MB.
A 4K clip at 50 Mbps with 320 kbps audio for 2 min 30 s: 50,320,000 × 150 ÷ 8 = 943,500,000 bytes = 943.5 MB.
Tips
- To plan a memory card, divide its capacity by the size of one minute to get the minutes it holds.
- Live streaming uses the same arithmetic per viewer: see the streaming bandwidth calculator for traffic across an audience.
- To hit a target size, work backwards with the video bitrate calculator.
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 get bytes. 8 Mbps video and 192 kbps audio for 10 minutes: 8,192,000 bit/s × 600 s ÷ 8 = 614,400,000 bytes, about 614.4 MB.
How much space does an hour of video take?
It depends only on the bitrate. At 5 Mbps of video plus 128 kbps of audio an hour is 2.31 GB; at 50 Mbps plus 320 kbps, as some cameras record 4K, it is about 22.64 GB. Enter your camera's or stream's bitrate to see your own figure.
Why does my file manager show a smaller number?
Windows counts in binary units (1 GB there = 1,073,741,824 bytes) but writes GB. The calculator shows both: GB in decimal units, as storage makers use, and GiB in binary units, which matches the Windows figure.
Is variable bitrate (VBR) footage covered?
Use the average bitrate. With VBR the size of a short clip can differ from the average, but over a long recording it comes close. The container adds a little overhead on top.