Video Bitrate Calculator
Estimate video file size from bitrate.
Results update as you type.
How it works
A video bitrate calculator estimates how large a video file will be from two inputs: how long it runs and the bitrate it is encoded at. Bitrate, measured in megabits per second, is the amount of data used to represent each second of footage, so it is the single biggest lever on file size and visual quality. This tool multiplies bitrate by duration and handles the bit-to-byte conversion to report the size in gigabytes and megabytes. The estimate is invaluable when planning storage, uploads, and streaming. Videographers checking whether footage fits a memory card, creators judging upload times, and streamers balancing quality against bandwidth all need to predict size before committing to an encode. It also makes the quality trade-off concrete: doubling the bitrate roughly doubles both the file size and the detail retained. The formula works because total data equals rate multiplied by time, once units line up. Multiplying minutes by sixty gives seconds, multiplying by bitrate gives megabits, and dividing by eight converts to megabytes. Real encodes using variable bitrate will vary around this figure, since complex scenes consume more data than simple ones, so treat it as a close average. Editors, streamers, and anyone managing video files rely on a bitrate calculator to size projects accurately.
size (MB) = bitrate (Mbps) × minutes × 60 ÷ 8
Bitrate measures how many megabits of data each second of video carries, so multiplying it by the length in seconds gives the total megabits. The duration is in minutes, so it is multiplied by 60 first. Dividing by eight converts megabits to megabytes, because a byte holds eight bits. The result is then divided by 1,024 to express the size in gigabytes for larger files.
Source:Standard digital media
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter duration and bitrate.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
File size updates instantly as you type — no button to press.
Frequently asked questions
What bitrate should I use for good quality?
It depends on resolution and content. As a rough guide, 1080p at 30 frames per second looks good around 8 Mbps, while 4K often needs 35 to 45 Mbps. Fast motion and fine detail demand higher bitrates to avoid blocky artefacts. Streaming platforms publish recommended ranges. Enter a candidate bitrate here to see how the file size changes before committing to a full export.
Why divide by eight in the formula?
Bitrate is quoted in megabits per second, but file sizes are measured in megabytes, and there are eight bits in a byte. After multiplying bitrate by the total seconds to get megabits, the calculator divides by eight to convert to megabytes. Forgetting this step would overstate the file size by a factor of eight, so the conversion is essential for a realistic estimate.
Does variable bitrate change the estimate?
Yes, somewhat. Variable bitrate encoding spends more data on complex, fast-moving scenes and less on simple, static ones, so the true size fluctuates around the average. This calculator assumes a constant average bitrate, which is a good approximation for the final size. If your encoder targets a specific average bitrate, the result will be close; scene-by-scene it will vary above and below.
How do I account for the audio track?
This calculator estimates the video stream from the bitrate you enter. If that bitrate already includes audio, the result covers the whole file. If it is video-only, add the audio separately: a typical stereo track adds about 128 to 320 kilobits per second, which over a long video can add tens of megabytes. For most estimates the audio contribution is small next to the video.
Can I use this to plan upload time?
Yes. Once you have the file size from this calculator, pair it with a download or upload time calculator using your connection's upload speed to estimate how long sending the file will take. This two-step approach is handy for creators uploading to video platforms, since large high-bitrate files can take considerable time on typical asymmetric home connections with limited upload speed.