Video duration equals the file size in bits divided by the total bitrate, or the frame count divided by the frame rate. A 1 GB file (8,000,000,000 bits) encoded at 8 Mbps runs 1000 seconds, which is 0:16:40. With frames, 86,400 frames at 24 fps make exactly one hour.
Editors, archivists and anyone planning storage often know a clip's size and bitrate, or its frame count, without having the file open in a player. This calculator turns either pair into a running time in hours, minutes and seconds, plus the same figure as total seconds, minutes and hours. It handles decimal units (MB, GB) and binary units (MiB, GiB), which differ by about 7 percent at the gigabyte scale. The size method assumes a constant total bitrate; variable-bitrate encodes give an estimate only, because the average bitrate a tool reports rarely matches the stream exactly, and container overhead adds a little size that carries no playing time.
Choose file size and bitrate, or frames and frame rate.
Type the file size and pick MB, GB, MiB or GiB inside the field. Windows Explorer shows binary sizes even though it labels them GB.
Use the overall bitrate in Mbps, video plus audio, from MediaInfo or your encoder settings.
Give the frame count and the frame rate, such as 23.976, 25 or 29.97 fps.
Result Running time (h:mm:ss): 0:16:40
Total seconds: 1,000
Total minutes: 16.67
Total hours: 0.278
A typical 1080p web encode. One decimal gigabyte holds 8 billion bits, which an 8 Mbps stream uses up in 1000 seconds.
Result Running time (h:mm:ss): 0:28:38
Total seconds: 1,717.99
Total minutes: 28.63
Total hours: 0.477
Older cards split clips at 4 GiB (FAT32). At 20 Mbps each split file holds a little under 29 minutes.
Result Running time (h:mm:ss): 1:00:00
Total seconds: 3,600
Total minutes: 60
Total hours: 1
Cinema frame rate: 24 frames a second means 86,400 frames make exactly one hour.
t = (S × B × 8) ÷ (R × 1,000,000) or t = N ÷ f
tSBRNfA byte is 8 bits, and bitrate prefixes are decimal, so 8 Mbps is 8,000,000 bits each second. Dividing the file's total bits by that rate gives the seconds of playback. For the frame method each frame lasts 1 ÷ f seconds, so N frames last N ÷ f. The seconds are then split into hours, minutes and seconds, rounded to the nearest whole second.
Most modern encodes use variable bitrate, and the average a tool reports is rounded. Container overhead also adds bytes that carry no picture or sound. Expect the size method to land within a few percent, not to the second.
A gigabyte (GB) is 1,000,000,000 bytes; a gibibyte (GiB) is 1,073,741,824 bytes. Windows shows GiB values but labels them GB, so a file Explorer calls 4 GB is 4 GiB, which holds about 7.4 percent more playing time at the same bitrate.
It depends on the bitrate. Streaming 4K at about 16 Mbps gives roughly 8 minutes 20 seconds per gigabyte, while a camera recording 100 Mbps fills a gigabyte in 80 seconds.
Yes. 2,997 frames at 29.97 fps last exactly 100 seconds, but at 30 fps they last 99.9 seconds. Over an hour that gap reaches about 3.6 seconds, which is why broadcast uses drop-frame timecode.
MediaInfo lists an Overall bit rate for the whole file, which is the figure to use here. Encoder presets in HandBrake, OBS or Premiere also state the target video and audio bitrates; add them together.
Not here; this page solves for time. For the reverse, the video file size calculator multiplies duration by bitrate to estimate storage.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 18). Video Duration Calculator. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/video-audio/media-utilities/video-duration-calculator/
Tools Directory Editorial Team. “Video Duration Calculator.” Tools Directory, 18 Oct. 2026, https://tools.milunir.com/video-audio/media-utilities/video-duration-calculator/. Accessed 26 Oct. 2026.
Tools Directory Editorial Team. “Video Duration Calculator.” Tools Directory. Last modified October 18, 2026. Accessed October 26, 2026. https://tools.milunir.com/video-audio/media-utilities/video-duration-calculator/.
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