Video File Size Calculator: Bitrate, Duration and GB
Video file size equals bitrate times duration divided by 8. At 220 Mb/s, Apple's target rate for ProRes 422 HQ at 1920 x 1080 and 29.97 fps, one hour is about 99 GB. At YouTube's recommended 8 Mbps for 1080p, one hour is about 3.6 GB before audio. This calculator does that arithmetic for you, or works backwards from a size to a bitrate.
Video file size calculator
Pick a preset or type your own bitrate, set the duration, and the size updates as you type. The numbers are saved in the page address so you can bookmark or share them. Nothing leaves your browser. Sizes use decimal gigabytes (1 GB = 1,000,000,000 bytes) and binary GiB is shown alongside.
How the video file size calculator works
A video file is a stream of bits per second for the picture and another for the sound. Multiply the total by the length of the clip and you have the number of bits in the file; divide by 8 for bytes. The calculator does exactly that and reports the result in megabytes, gigabytes and gibibytes.
bit/s = video Mbps × 1,000,000 + audio kbps × 1,000 bytes = bit/s × seconds ÷ 8 GB = bytes ÷ 1,000,000,000 GiB = bytes ÷ 1,073,741,824 total Mbps = GB × 8,000 ÷ seconds video Mbps = total Mbps − audio kbps ÷ 1,000
- seconds
- hours × 3,600 + minutes × 60 + seconds
- video Mbps
- megabits per second of the video stream
Worked example
Given: 1 hour of video; Apple ProRes 422 HQ at 1920 x 1080, 29.97 fps (220 Mb/s); no audio counted.
- Bits per second:
220 × 1,000,000 = 220,000,000 - Bytes in one hour:
220,000,000 × 3,600 ÷ 8 = 99,000,000,000 - In gigabytes:
99,000,000,000 ÷ 1,000,000,000 = 99 GB
Answer: 99 GB per hour, the same figure Apple lists in its white paper table (about 92.2 GiB).
Published bitrates used
| Profile | 24p | 30p | 60p |
|---|---|---|---|
| Proxy | 36 | 45 | 91 |
| LT | 82 | 102 | 204 |
| 422 | 117 | 147 | 293 |
| 422 HQ | 176 | 220 | 440 |
| 4444 | 264 | 330 | 660 |
| 4444 XQ | 396 | 495 | 990 |
| Profile | 24p | 30p | 60p |
|---|---|---|---|
| Proxy | 145 | 182 | 363 |
| LT | 328 | 410 | 821 |
| 422 | 471 | 589 | 1178 |
| 422 HQ | 707 | 884 | 1768 |
| 4444 | 1061 | 1326 | 2652 |
| 4444 XQ | 1591 | 1989 | 3977 |
Source 1. Apple's paper lists 24, 25, 30, 50 and 60p; the 30p column is the 29.97 fps figure used in its text. 4444 and 4444 XQ are without alpha.
| Source | Setting | Bitrate | Source no. |
|---|---|---|---|
| YouTube | 1080p SDR, 24/25/30 fps | 8 Mbps | 2 |
| YouTube | 1080p SDR, 48/50/60 fps | 12 Mbps | 2 |
| YouTube | 4K SDR, 24/25/30 fps | 35 to 45 Mbps | 2 |
| YouTube | stereo audio | 384 kbps | 2 |
| Sony XAVC S | 4K, 100 / 60 Mbps modes | max 100 / max 60 Mbps | 3 |
| Sony XAVC S | HD 50 / 25 / 16 Mbps modes | approx. 50 / 25 / 16 Mbps | 3 |
| DJI Osmo Action 4 | max video bitrate | 130 Mbps | 4 |
| DJI Mini 4 Pro | max video bitrate | 150 Mbps | 5 |
Each row was read from the maker's page on 2026-11-13.
Assumptions and limits
- The result is the size of the media streams. A container such as MOV or MP4 adds a small overhead for headers and an index, which is not included.
- Presets are the makers' published target, maximum or recommended figures. ProRes and most camera codecs are variable bitrate, so real files differ with picture content.
- Only the ProRes figures at 1920 x 1080 and 3840 x 2160 are in the presets; the white paper lists many more sizes. Use the custom option for others.
- Camera modes not listed in the cited pages (for example newer Sony 150 and 200 Mbps modes) are unconfirmed here.
- Frame rate and resolution are not inputs: the bitrate already reflects them. Interlaced or odd rates need a custom bitrate.
- This page does the arithmetic only and does not recommend conversion software.
Frequently asked questions
How do I calculate video file size from bitrate?
Add the video and audio bitrates in bits per second, multiply by the duration in seconds, and divide by 8 to get bytes. For example, 8 Mbps video plus 384 kbps audio is 8,384,000 bit/s, which over one hour (3,600 s) is 3,772,800,000 bytes, or about 3.77 GB. Real files run a little larger because of container overhead, which this calculator does not model.
How big is one hour of ProRes?
Apple's ProRes white paper lists target data rates and gives gigabytes per hour for each. At 1920 x 1080 and 29.97 fps (the paper's table column is labelled 30p) the target rates are 45 Mb/s for 422 Proxy, 102 for 422 LT, 147 for 422 and 220 for 422 HQ. At 220 Mb/s one hour is 99 GB, which matches the paper's own table. Actual files vary with picture content because ProRes is variable bitrate.
Is a GB 1,000 MB or 1,024 MB?
The calculator shows both. Storage makers and the Apple white paper count 1 GB as 1,000,000,000 bytes. Some operating systems report 1 GiB, which is 1,073,741,824 bytes, under the label GB, so the same file can look about 7% smaller there.
What bitrate should I export for YouTube?
YouTube publishes recommended upload bitrates for H.264 SDR: 8 Mbps at 1080p and 35 to 45 Mbps at 4K for 24, 25 or 30 fps, and 12 Mbps at 1080p for 48, 50 or 60 fps. They are recommendations for reference, not limits, and YouTube says no bitrate limit is required. Choose a YouTube preset above to see the size.
How do I find the bitrate for a target file size?
Switch the mode to "Find the bitrate for a target size". It converts the size to bits, divides by the duration, then subtracts the audio bitrate. That figure is the average video bitrate that makes the file that size. It is an average: a constant-bitrate encode will hit it closely, while a variable-bitrate encode needs a two-pass or target-size mode in your encoder.
Do the presets give the exact size of my camera files?
No. Camera presets use the bitrate the maker publishes, usually a maximum or approximate figure. Sony's help guide lists XAVC S 4K as "Max. 100 Mbps" and XAVC S HD 50 Mbps as "Approx.", and DJI lists a "Max Video Bitrate". Your files will be at or below those figures depending on the scene. Other camera modes, such as 150 or 200 Mbps on newer Sony bodies, are unconfirmed here, so use the custom option for them.
Does this tell me which converter to use?
No. It only does the arithmetic. It does not recommend or compare conversion software.
Sources
- Apple, Apple ProRes White Paper (April 2017): target data rates (apple.com) Accessed 2026-11-13.
- YouTube Help, YouTube recommended upload encoding settings: video and audio bitrates (support.google.com) Accessed 2026-11-13.
- Sony, FDR-AX700 Help Guide: bit-rate and recording pixels (XAVC S) (helpguide.sony.net) Accessed 2026-11-13.
- DJI, Osmo Action 4 specs: max video bitrate (dji.com) Accessed 2026-11-13.
- DJI, Mini 4 Pro specs: max video bitrate (dji.com) Accessed 2026-11-13.