Why resolution matters as much as format
File size depends on resolution as much as it depends on codec — often more. An uncompressed 4K frame has four times the pixels of 1080p, so resolution can have a major effect on file size. For formats such as RAW and uncompressed video, the relationship can be calculated directly; for professional codecs such as ProRes and DNx, the calculator uses documented data rates for each supported resolution.
For that reason, the resolution options only show what's actually documented for the selected format — some formats like ProRes have published data at several resolutions, while others (Avid DNxHD, for instance) only have a single documented reference point. Rather than guess at untested combinations, the calculator only offers resolutions it has real data for.
How the estimate is calculated
This calculator uses three different approaches depending on how each format actually behaves:
- Documented data rates — Apple ProRes, Avid DNx, Sony XAVC, Canon XF-AVC, Panasonic AVC-Intra, and Apple Intermediate Codec use documented or estimated reference data rates at specific resolutions. The calculator only offers resolutions with documented data rates for these formats, rather than extrapolating to unsupported resolutions.
- Sensor-data math — Blackmagic RAW and REDCODE RAW compress a fixed ratio of the camera's raw sensor data (a "5:1" file really is one-fifth the size of the unprocessed sensor data), so file size is computed directly from resolution, frame rate, and the selected ratio.
- Direct formula — Some formats can be calculated directly from resolution and frame rate rather than using a resolution-specific bitrate table. This includes uncompressed video, CineForm, DPX, OpenEXR, and TIFF sequences.
Delivery codecs (H.264, H.265, AV1, VP9, VP8, MPEG-2, MPEG-4 Part 2) are the least predictable of the group — their actual bitrate depends heavily on content complexity and encoder settings, so these use typical/recommended-quality bitrates rather than a fixed target. Treat those numbers as a reasonable starting estimate, not a guarantee.
Frequently asked questions
Why does the calculator ask for resolution when I only wanted to check a format?
Because resolution has a major effect on file size, especially for professional and uncompressed formats. The same format can produce dramatically different file sizes at different resolutions, so leaving resolution out would make the estimate much less useful.
How accurate is this calculator?
Formats with defined or predictable data rates—such as ProRes, DNx, XAVC, AVC-Intra, RAW, and uncompressed formats—can be estimated much more consistently than delivery codecs. Delivery codecs such as H.264 and H.265 can vary substantially with content complexity and encoder settings, so their figures are typical estimates rather than fixed targets.
What does a RAW compression ratio like "5:1" actually mean?
It's measured against the camera's own unprocessed sensor data. A "5:1" file is one-fifth the size of what the sensor captured before any compression — a lower ratio (like 3:1) means less compression and a larger file; a higher ratio (like 12:1) means more compression and a smaller one.