Proxy Media Storage Calculator
Estimate the disk space a set of editing proxies will use from your footage duration and the proxy bitrate, and compare it to the originals.
How it works
Size (GB) = bitrate (Mbps) · seconds ÷ 8 ÷ 1000 · seconds = hours · 3600
Proxies are lightweight stand-ins for heavy source footage that let an editor scrub and cut smoothly, then relink to the originals for final export. Their storage cost is just bitrate times duration: a bitrate in megabits per second times the runtime in seconds, divided by 8 to get megabytes and by 1,000 to reach gigabytes. Because proxies run at a fraction of the original bitrate, they add only a modest overhead on top of the source media.
Worked example
4 hours (14,400 s) of footage with a 30 Mbps proxy: 30 × 14,400 ÷ 8 ÷ 1000 = 54 GB of proxies. The 150 Mbps originals take 270 GB, so proxies are 80% smaller and the combined project needs about 324 GB.
Frequently asked questions
What proxy bitrate should I use?
Enough for smooth editing without wasting space. ProRes Proxy at 1080p runs around 45 Mbps; an H.264 or HEVC proxy at 10–30 Mbps is far smaller and fine for offline editing. Match the proxy resolution to your monitor — 1080p proxies are usually plenty even for 4K sources.
Do I still need the original files?
Yes. Proxies are for editing performance only; the final render relinks to the full-quality originals so you keep every pixel of the source. Keep both until the project is delivered and archived — this calculator shows the combined footprint for exactly that reason.
Does GB here mean 1000 or 1024 megabytes?
This uses decimal gigabytes (1 GB = 1,000 MB), which is how drive manufacturers and most bitrate math label capacity. Your operating system may report slightly smaller "GiB" figures because it divides by 1,024, so leave a little margin.
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This calculator is for educational purposes. Double-check important results before acting on them.