Video File Size Calculator
Find a video's file size from its bitrate and length — or the bitrate that fits under a size limit.
Runs in your browser. Nothing to upload — the numbers are worked out instantly.
Presets are YouTube's recommended upload bitrates for each resolution.
Estimated file size
581 MB
8 Mbps video + 128 kbps sound for 10 minutes.
How to calculate video file size
A video's size depends on two things: its bitrate — how much data each second of picture and sound uses — and its length. Choose a quality preset (or type your own bitrate), enter the length, and the size appears straight away. To go the other way, choose Bitrate for a target sizeand enter the size you need to stay under.
The formula
File size = (video bitrate + sound bitrate) × length ÷ 8. Bitrates are in bits per second, and there are 8 bits in a byte. So 8 Mbps video with 128 kbps sound for 10 minutes is 8.128 × 600 ÷ 8 = 610 million bytes, about 581 MB. The calculator shows sizes in the same megabytes as Windows and our compressor.
Typical sizes per minute
| Quality | Bitrate | 1 minute | 10 minutes | 1 hour |
|---|---|---|---|---|
| 4K (2160p), 60 fps | 60 Mbps | 430 MB | 4.20 GB | 25.2 GB |
| 4K (2160p), 30 fps | 40 Mbps | 287 MB | 2.80 GB | 16.8 GB |
| 1440p, 30 fps | 16 Mbps | 115 MB | 1.13 GB | 6.76 GB |
| 1080p, 60 fps | 12 Mbps | 87 MB | 867 MB | 5.08 GB |
| 1080p, 30 fps | 8 Mbps | 58 MB | 581 MB | 3.41 GB |
| 720p, 30 fps | 5 Mbps | 37 MB | 367 MB | 2.15 GB |
| 480p, 30 fps | 2.5 Mbps | 19 MB | 188 MB | 1.10 GB |
| 360p, 30 fps | 1 Mbps | 8.1 MB | 81 MB | 484 MB |
With 128 kbps sound. Phones and cameras often record at higher bitrates than these, so their files are bigger.
Fitting a video under a size limit
When a site or app has a limit — 25 MB for email, 20 MB for Discord — the length decides how much bitrate you can afford. Less bitrate means you should also lower the resolution: a clean 720p picture looks better than a blocky 1080p one at the same size. This is what fits in 25 MB:
| Clip length | Resolution | Video | Sound | Expect |
|---|---|---|---|---|
| 30 seconds | 1080p | 6,723 kbps | 128 kbps | Sharp |
| 1 minute | 720p | 3,297 kbps | 128 kbps | Sharp |
| 2 minutes | 540p | 1,585 kbps | 128 kbps | Good on phones |
| 5 minutes | 360p | 589 kbps | 96 kbps | Watchable, soft |
| 10 minutes | 270p | 295 kbps | 48 kbps | Watchable, soft |
The Video Compressor does all of this for you: tell it the size and it picks the bitrate and resolution, then checks the finished file is under the limit.
Frequently asked questions
How do I calculate video file size?
File size = bitrate × length. Add the video and audio bitrates, multiply by the length in seconds, and divide by 8 to turn bits into bytes. For example, 8 Mbps video plus 128 kbps sound for 10 minutes is 8.128 × 600 ÷ 8 ≈ 610 million bytes, which Windows shows as about 581 MB. The calculator above does this for you, and real files usually come out within a few percent.
How big is a 1-minute 1080p video?
At YouTube's recommended 8 Mbps, about 58 MB per minute at 30 fps, and about 87 MB at 60 fps (12 Mbps). Phones often record at a higher bitrate than that, so a minute straight off the camera can be 100 MB or more.
What bitrate do I need to fit a video under a size limit?
Switch to "Bitrate for a target size", enter the size and the length, and the calculator shows the video and sound bitrates that fit, plus the resolution that will look best at that bitrate. These are the same numbers our Video Compressor uses, so you can compress straight to that size.
What is a good bitrate for 1080p?
For uploading, YouTube recommends 8 Mbps at 30 fps and 12 Mbps at 60 fps. For sharing, much less is fine: 2–4 Mbps looks good on a phone screen. Below about 1.5 Mbps, 1080p starts to look blocky, and a lower resolution will look cleaner.
Why is my real file a different size?
Most cameras and phones use a variable bitrate, spending more on busy scenes and less on still ones, so the average they actually use is not the number on the spec sheet. The calculator is exact for a given average bitrate; if you know the file's real size and length, you can work backwards to its average bitrate.
Is MB here 1,000,000 or 1,048,576 bytes?
1,048,576 bytes (1024 × 1024) — the same as Windows File Explorer and our video compressor. macOS and phones count 1,000,000, so they show the same file as about 5% bigger.