DataCalc
Video Duration ↔︎ File Size Calculator
Video duration and file size calculator. Quickly estimate storage needs, convert between duration and file size, and plan media storage for any video format.
How this calculator works
The Duration ↔︎ File Size calculator converts between video runtime and storage in both directions: enter a duration to see how much space a recording will take, or enter an available file size to see how many minutes you can store. It works with any codec and resolution because file size is a pure function of data rate and time.
Editors and producers use it to budget storage for a project, DITs use it to sanity-check offloads, and camera assistants use it to answer the classic on-set question: "will this take fit on the card?"
File size from duration and bitrate
File Size (GB) = Bitrate (Mb/s) × Duration (seconds) ÷ 8,000
Example: a 10-minute clip at 100 Mb/s → 100 × 600 ÷ 8,000 = 7.5 GB.
| Codec / setting | Data rate | Storage per hour |
|---|---|---|
| H.264, 1080p streaming quality | 10 Mb/s | 4.5 GB |
| H.264, high-quality 1080p | 50 Mb/s | 22.5 GB |
| H.265/HEVC, UHD acquisition | 100 Mb/s | 45 GB |
| ProRes 422, 1080p @ 23.976 | ≈117 Mb/s | ≈53 GB |
| ProRes 422 HQ, 1080p @ 23.976 | ≈176 Mb/s | ≈79 GB |
| ProRes 422 HQ, UHD @ 23.976 | ≈707 Mb/s | ≈318 GB |
Data rates are approximate; actual sizes vary slightly with content and encoder.
Frequently asked questions
How big is one hour of 4K video?
It depends entirely on the codec. One hour of UHD footage is roughly 45 GB at H.265 100 Mb/s, about 318 GB in ProRes 422 HQ, and well over a terabyte in many RAW formats. Enter your exact codec and bitrate in the calculator above for a precise number.
How much video fits on a 1 TB drive?
At 50 Mb/s (high-quality H.264), about 44 hours. In ProRes 422 HQ UHD, roughly 3 hours. Divide drive capacity by the storage-per-hour figure for your codec — or run the calculation in reverse with this tool by entering the file size.
Why is my file smaller than the calculator predicts?
Variable-bitrate (VBR) codecs like H.264 and H.265 use less data on simple or static images, so real files often come in under the nominal bitrate. Constant-bitrate professional codecs like ProRes and DNxHR track their published data rates much more closely.
Does frame rate change file size?
Yes — for intraframe codecs like ProRes, data rate scales roughly linearly with frame rate: 59.94p ProRes is about 2.5× the size of 23.976p at the same resolution. For long-GOP codecs the encoder targets a set bitrate, so frame rate matters less than the bitrate you choose.
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