Video Bitrate Calculator
Mbps
sec
File Size600 MB
Size in GB0.600 GB
The Video Bitrate Calculator links three quantities: bitrate, duration, and file size. Give it any clip bitrate in megabits per second and its length in seconds and it predicts the output file size, or switch modes to find the bitrate you must encode at to fit a clip inside a storage or upload limit. It uses the standard media convention where eight megabits make one megabyte.
Formula
sizeMB = bitrateMbps × durationSeconds / 8; bitrateMbps = sizeMB × 8 / durationSeconds
- bitrateMbps
- Average encoding bitrate in megabits per second
- durationSeconds
- Length of the clip in seconds
- sizeMB
- Resulting file size in megabytes
How it works
- In File Size mode, enter the encoding bitrate in Mbps and the clip duration in seconds; the size in megabytes is bitrate × duration ÷ 8.
- In Required Bitrate mode, enter a target file size in megabytes and the duration; the calculator rearranges the formula to give the bitrate in Mbps and kbps.
- The result accounts only for the encoded video and audio stream, so leave a little headroom for container overhead when targeting a hard limit.
Worked example
A 10-minute (600 second) clip encoded at 8 Mbps.
- Convert duration: 10 minutes = 600 seconds.
- Size = 8 × 600 ÷ 8 = 600 megabits ÷ 8.
- Size = 600 MB.
The clip is about 600 MB (0.6 GB).
Frequently asked questions
- What bitrate should I use for 1080p video?
- Streaming services suggest roughly 8 Mbps for 1080p at 30 fps and around 12 Mbps at 60 fps. Higher motion or detail benefits from more, while talking-head footage compresses well at less.
- Why does the calculator divide by 8?
- Bitrate is measured in megabits but files are measured in megabytes, and one byte is eight bits. Dividing megabits by eight converts the data rate into a storage size.
- Is the file-size estimate exact?
- It is close for constant-bitrate encodes but treats bitrate as an average. Variable-bitrate encoding and container overhead can shift the real size by a few percent.
- How do I fit a video under an upload limit?
- Use Required Bitrate mode: enter the size cap and the clip length, and it returns the highest average bitrate that stays within the limit so you can set it in your encoder.